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(IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 Speed Response and Performance Degradation of High Temperature Gamma Irradiated Silicon PIN Photodiodes Abd El-Naser A. Mohamed1, Nabil A. Ayad2, Ahmed Nabih Zaki Rashed1* and Hazem M. El-Hageen1, 2 1 Electronics and Electrical Communication Engineering Department, Faculty Electronic Engineering, Menouf, 32951, Egypt 2 Atomic Energy Authority, P.O. Box 29, Naser City, Cairo, Egypt * E-mail: ahmed_733@yahoo.com Abstract─In the present paper, we have been investigated by the internal field. With no external voltage applied, this deeply and parametrically the speed response of Si PIN internal field will prevent the majority carriers to cross the photodiodes employed in high temperature-irradiated junction. Minority carriers however are still capable of environment. The radiation-induced photodiodes defects can reaching the junction by diffusion and give rise to leakage modify the initial doping concentrations, creating generation- current. Electron-hole pairs generated outside the depletion recombination centres and introducing trapping of carriers. Additionally, rate of the lattice defects is thermally activated and region will most likely recombine, consequently not reduces for increasing irradiation temperature as a result of contributing to the photocurrent [3]. annealing of the damage. Nonlinear relations are correlated to The current–voltage technique is used to measure the rate investigate the current-voltage and capacitance-voltage of carrier creation and so the generation or the recombination dependences of the Si PIN photodiodes, where thermal and rate [4]. On the other hand, the capacitance–voltage technique gamma irradiation effects are considered over the practical in reverse bias direction, is used to determine doping profiles ranges of interest. Both the ambient temperature and the of a semiconductor [4–6]. The capacitance measurements give irradiation dose possess sever effects on the electro-optical information about fixed impurity states and defect centers in characteristics and consequently the photo-response time and the band gap. Device testing, adequate system shielding and SNR of Si PIN photodiodes. In this paper, we derive the transient response of a Si PIN photodiode for photogeneration currents, radiation tolerant design are some fundamental steps in the when it is exposed to gamma radiation at high temperature. An methodology or in the radiation hardness assurance [7] that exact model is obtained, which may be used to optimize the are needed to ensure the correct performance and efficiency of responsivity and speed of these irradiated devices over wide electronics during system life. But, there is an increasing range of the affecting parameters. interest in the development of accurate modeling and simulation techniques to predict device response under Keywords: Radiation effects, PIN photodiode, Optoelectronics, different radiation conditions [8]. Transient current, Dark current, Photocurrent, Quantum efficiency, Responsitivity. In the present study, we have been investigated and analyzed parametrically and numerically the modeling basics I. INTRODUCTION of a PIN photodiode device with the maximum possible Since several years, photonic and lightwave technology precision, in order to predict the frequency response behaviour is seriously considered for optical access communication and of Si PIN photodiodes when they were irradiated to different monitoring applications in space borne local communication dose of high-temperature gamma radiation environments over systems and nuclear projects. A major problem in these wide range of the affecting parameters. environments is the presence of radiation fields. Two types of damage affect the electronic devices when they are exposed to II. Physical Modeling Basics the radiation [1]. The first one is ionization damage, it is a Radiation damage produces defects which can result in transitory damage. In contrast, displacement damage is three main effects on photodiode devices as following: considered permanent. For several reasons, the interest of - The increase in dark current can be related to the minority study of the effects of performance of devices in high- carrier lifetime of the semiconductor if the generation- temperature electronics is developing rapidly. If these recombination is dominated by mid-band levels caused by components are to be used in a radiation environment, defects. Another source affecting the dark current could be knowledge about the degradation under high-temperature ionizing damage to the surface of the device. irradiation conditions is highly desirable [2]. Optical - Degraded photocurrent as defects act as electron or hole communication devices in close proximity to radiation fields trapping centers for the photogenerated pairs. The defects may such as those present in terrestrial orbits and high-energy be primary defects, i.e. defects which originate directly from accelerators suffer both long term effects due to total dose and atomic displacements, or secondary defects resulting from the displacement damage from non-ionizing energy-loss, as well interaction of mobile primary defects with impurities. Many as short term or transient effects due to local ionization from defects will recombine leading to an immediate repair of the nuclear reactions and high-energy recoils generated close to or lattice. However, some will combine to form stable defects within the depletion volume of a device. A photodiode works such as interstitials, di-vacancies, vacancy-impurity by generating current from photons absorbed in its active complexes, vacancy-dopant complexes, and larger clusters. area. In a semiconductor material, a region depleted of These defects form effective recombination and trapping mobile charge carriers is formed near the P-N junction. This centers resulting in a decrease in the minority carrier lifetime, zone is called depletion region. Incident radiation within this carrier density and carrier mobility. Defect centers position in region will create electron-hole pairs, immediately separated the band gap determines their activity and hence the 268 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 conduction mechanism in devices made from such material the following parameters; type and energy of the incident [9]. Deep traps are defects whose ionization energy, E, is particle, kind of material, resistivity, types and concentration much greater than kBT (kB is the Boltzmann constant and T is of impurities, injection level, temperature and elapsed time the temperature). They trap free carriers with the consequence after irradiation [14, 15]. Also a semiconductor p–n junction that they reduce the conductivity considerably. In contrast, acts as a capacitor. The depletion region capacitance of a shallow traps are easily ionized at equilibrium since ∆E << uniformly doped lifetime diode at full depletion may be kBT, and so they increase the conductivity by releasing expressed in terms of the dielectric constants ε0, εr. In this trapped carriers. In depleted regions they contribute to the situation the effective carrier concentration is evaluated: space charge and the voltage required for full depletion. 2C 2 N eff = V (2) Generation–recombination (g-r) centers are situated near the qε rε 0 A 2 centre of the band gap, in which position their trapping for Where A is the active diode area, q is the electronic charge electrons and for holes is comparable, and so they easily and V is the full depletion voltage. This relation shows that generate or recombine e–h pairs. Then the free carriers are Neff α VC2, which may be simplified to V α C−2 for a constant removed to reduce the conductivity. Defect centers can also effective carrier concentration, which is the case for uniform act as compensation centers in the electrical neutral bulk of a doping and is assumed for lifetime material. In any semiconductor. Here, the deep levels are not easily ionized at semiconductor, a rise in temperature will increase the current, equilibrium and have the effect of locking away free carriers since carriers become thermally activated to increase the to reduce the conductivity. The response degradation [8] is effective carrier density, Neff, so that the current I α Neff. An probably related to type inversion of the low-doped layer from increase in light intensity is expected to have the same effect n to p-type. At low integrated fluence, the radiation forming [9]. Because the current is ohmic and is generated in the acceptor state levels compensate the donor states until the whole of the depletion region, the depletion width becomes a effective doping concentration Neff is reduced to that of the function of depletion voltage. The capacitance becomes a intrinsic semiconductor. At higher fluences, the effective function of radiation and temperature since electrons and doping is mainly provided by the radiation induced defects. holes are thermally activated. The concentration of majority carriers decreases with the irradiation fluence. III. Modeling Description - Degraded rise and fall times due to de-trapping or a reduction in the carrier mobility [10]: The decrease in A) Optical and electrical properties analysis photocurrent and the increase in the dark current are expected The dark current, ID, for a device having depletion depth W, to be the major changes in thin junction devices such as active area A and the effective carrier concentration, Neff photodiodes. The change in the device response, rise and fall under high temperature irradiation T and gamma radiation times are expected to be small, but still require measuring. fluence γ is given by [15, 16]: Three main factors limit the speed of response of a qAW (T , γ ) N eff (T , γ ) photodiode. These are [11]: ID = (3) 2τ r (T , γ ) a) The drift time of the carriers through the depletion region; b) The diffusion time of the carriers generated outside the Where τr is the minority carrier lifetime after irradiation and it depletion region; is given by [9, 12]: 1/τ r = 1/τ 0 + Kr γ (4) c) The time constant incurred by the capacitance of photodiode with its load and its associated circuit. Where τ0 denotes the pre-irradiation minority carrier lifetime Photons that penetrate the semiconductor can be respectively, and Kr is the damage coefficient for τr. Assuming absorbed and its energy can be utilized in the generation of e– a linear relationship between damage increase and fluence, the h pairs. The model that describes the rate of generation is [12]: damage coefficient for dark current KD and light photocurrent p α KP, can be defined by following equation [15]: G opt ( x ) = (1 − r )η 0 exp( −α x ) (1) hν ΔI D , P = I D , P (γ ) − I D , P (0) = K D , P γ (5 ) A where r is the reflection coefficient, Previous reports in simple model of the annealing can be constructed if we literature have stated that is independent of dose for 1 MeV assume that the radiation-induced defects anneal according to electron irradiations up to 5×1015 cm-2 [13]. η is the quantum a first-order mechanism (exponential recovery) [17], at a efficiency, P0 is the incident light intensity, h is the Planck given absolute high temperature irradiation T, KD can be constant, ν is the photon frequency, α is the absorption related to an activation energy E by the Arrhenius formula: coefficient and x is the depth variable. The optical spectral K D (T ) = K D (0) exp(E / K BT ) (6) response of a PIN photodiode is called the optical sensitivity Where KB, is Boltzmann’s constant. or the responsivity and it is related to the total photon-induced Based on the data of [18-20], the following nonlinear thermal current. If the width of the p-layer is much thinner than 1/α, and radiation relations for the set Si PIN photodiode: the photon-induced current in the p-layer does not contribute I Dark , Photo ( T , γ ) = I Dark , Photo ( T ) × I Dark , Photo (γ ) (7) to the total photocurrent. − 24 ⎫ I Dark = I Dark ( 0 ) + 3 . 29 × 10 exp( 831 )×γ The current–voltage and capacitance-voltage T ⎪ ⎛ − 1 . 137 × 10 − 11 T 2 ⎞ ⎪ characteristics, in the dark and under illumination are highly ⎜ ⎟ ⎪ ⎬ (8 ) sensitive to the radiation-induced change of the minority I Photo = I Photo ( 0 ) − 7 . 8 × 10 − 14 ⎜ + 6 . 536 × 10 − 9 T ⎟ × γ ⎪ ⎜ −8 ⎟ ⎪ carrier lifetime τ. In general, the damage coefficients for the ⎜ + 8 . 207 × 10 ⎝ ⎟ ⎠ ⎪ ⎭ mean minority carrier lifetime in semiconductors depend on The drift current density of PIN photodiode is given as: 269 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 W qp 0 (1 − r f ) Where T is the ambient temperature, γ is irradiation fluence, j drift = q ∫ G opt ( x ) dx =q ϕ 0 (1 − e − α W ) = (1 − e − α W ) ( 9 ) 0 ah υ C0/a1=1.176×10-9, a2=0.001052,.β=1.139×10-15 and V=-1volt. The one-dimension diffusion equation for initial minority The depletion width W can be expressed as the following [9] holes Pn0 in the bulk n region is [11, 21] 2 ε ( V + V bi ) W = = 2 ερμ ( V + V bi ) ( 21 ) ∂ 2 pn pn − pn0 qN eff DP − + G opt ( x ) = 0 (10 ) ∂x 2 τ p ε 0ε r A W = ( 22 ) 1 pn0 ϕ α −αx C pn2 − ( ) pn = − − 0 e (11) L2 p L2p DP Where A is the effective photodiode area, q is the electronic charge, Neff is the carrier concentration, εr is the dielectric L2 K BT Dp = p = μ (12 ) constant of silicon, ε0 is the vacuum permittivity. From the τp q previous results [4, 5], we can observed that εr is constant for Where τp, LP and Dp are minority carrier life time, diffusion radiation but it is function of temperature as [22]: length and diffusion constant and μ is the carrier mobility. ε r (T ) Si ≈ 11 . 631 + 1 . 0268 × 10 − 3 T + 1 . 0384 × 10 − 6 T 2 The solution of Eq. 11 under the boundary conditions Pn=Pno − 8 . 1347 × 10 − 10 T 3 ( 23 ) for x=∞, and Pn=0 for x=W. The Tauc model [23] has been used as a stander model Dp αL p j diffu = qp n 0 + qϕ 0 ( ) e −α W (13) whereby the optical gap of an amorphous semiconductor may Lp 1 + αL p be determined as: j total = j drift + j diffu (14 ) α ( hν ) = α 0 ( hν − E g ) 2 ( 24 ) αL p − 1 − αL p −αW Dp Where 1/α0 is the band edge parameter and Eg is energy gap. j total = q ϕ 0 (1 + e ) + qp n 0 (15 ) 1 + αL p Lp The energy gap of the perfect silicon as a function of the Under normal operating conditions, the dark-current term temperature is given by [24]: involving pno is much smaller so that the total photocurrent is 4 .731 × 10 − 4 T 2 E g = 1 .166 − ( 25 ) proportional to the incident photon flux per unit area, φ0 . 636 + T But under irradiation condition the total photocurrent is But for imperfect semiconductor as a result of radiation given by [9]: induced defects the energy band gab Eg is replace by Tauc I total = I Photo + I Dark (16 ) bandgap energy EgTauc [23], then α will became: Where Itotal is the current measured under illumination, IDark α Tauc (hν ) = α 0 (hν − E g Tauc ) 2 (26) is the current measured in the dark, Iphoto is the current due to In this case the residual absorption near the bandgap due to the the illumination only. The high-temperature irradiation intragap is called the Urbach tail [25], and can be expressed induce diffusion length change can be expressed as the with the following equation close to the bandgap: following expression: ⎛ (hυ − E g ) ⎞ aqp 0 (1 − r f ) e −α W α Urb ( h υ ) = A 0 exp ⎜ ⎜ ⎟ ⎟ ( 27 ) I photo = j photo × a = (1 − ) (17 ) ⎝ E Urb ⎠ hυ 1 + αL p We need a function for α that is valid for the entire spectral I photo range, i.e. an equation that combines (15) and (16) is smooth 1 − e α W (1 − ) ⎛ 1 ⎞ aq ϕ 0 at the cross point, Ecross: Lp = ⎜ ⎜α ⎟ ⎟ (18 ) I photo α Tauc ( E cross ) = α Urb ( E cross ) ( 28 ) ⎝ s ⎠ e α W (1 − ) aq ϕ 0 ′ ′ α Tauc ( E cross ) = α Urb ( E cross ) ( 29 ) Where a is the photodiode area. By comparing the different Where α' denotes the first derivative with respect to the cases of the depletion layer width, the junction capacitance energy. With equations (28) and (29) the following conditions and the inverse of the absorption coefficient, a reasonable are obtained: compromise between high-frequency response and high ⎛ ⎛ 1 α0 ⎞⎞ Eg = E g − 2 E Urb ⎜ 1 + ln ⎜ ⎟⎟ ( 30 ) quantum efficiency of photodiode is found for absorption Tauc ⎜ ⎜ 2 E Urb A0 ⎟ ⎟ ⎝ ⎝ ⎠⎠ region thicknesses between 1/α and 2/α. EUrb (T ) = E u 0 × T ( 31) W ⎛ I photo ⎞ αW = = − ln ⎜ (1 + α s L p )( 1 − )⎟ (19 ) Where Tauc and Urbach parameters of silicon material are (1 / α ) ⎜ aq ϕ 0 ⎟ ⎝ ⎠ A0=800cm-1, Eu0=36 Mev [25], and α0=4685cm-1 [26]. Irradiation induced change of the depletion layer width and the absorption coefficient must be take into consideration. B) Photodiode response analysis Based on Eq.2 and the results of [5, 6] which shows the variation of the effective carrier concentration, Neff of Si PIN The responsitivity, S, of a PIN photodiode can be expressed photodiode with electron irradiation dose. The depletion layer as: I photo qη capacitance with its initial value C0, when a voltage V is S (T , γ ) = = (32) Wh P0 hυ applied to a junction with the built-in potential (Vbi (Si)~0.65v [9]), is given by: ere the quantum efficiency, η, can be given by: C0 exp( − βγ ) (1 + a 2 T ) I photo / q ⎛ e −α W ⎞ C (T , γ ) = × ( 20 ) η (T , γ ) = = (1 − R f ) ⎜ 1 − ⎟ ( 33 ) a1 P0 (1 − r ) / h ν ⎜ 1 + αL p ⎟ V + V bi ⎝ ⎠ In order to analyze the response time of irradiated PIN photodiode, assume a modulated photon flux density as: 270 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 ϕ = ϕ 0 exp( j ω t ) photons /( s .cm 2 ) ( 34 ) Where W0 is the substrate thickness. Finally, for fully To fall on photodiode, where ω is the sinusoidal modulation depleted photodiodes the rise time tr and fall time are frequency. The total current through the depletion region generally the same. generated by this photon flux can be shown to be [21, 27]: 2 2 2 tr = t dr + t Df + t RC ( 42 ) ⎛ jωε ( V + Vbi ) 1 − e − jω t dr ⎞ ⎟ e jω t Finally the power signal-to-noise ratio (SNR) S/N at the J tctal = ⎜ + qϕ 0 (35 ) ⎜ W jω t dr ⎟ ⎝ ⎠ output of an analog optical receiver is defined by [11]: ⎛ ω t dr⎞ 0.5m2 I 2 photo Sin 2 ⎜ ⎜ 2 ⎟ ⎟ ⎛ ω ε ( V + V ) ⎞ ⎛ ω ε ( V + V ) ⎞2 S/N= (43) I total ⎝ ⎠⎜ bi ⎟ ⎜ bi ⎟ (2qf−dB(I photo + I Dark) + 4K BTf−dBFn / RL ) = 1− + (36 ) a q ϕ0 2 ⎜ ⎟ W (ω t dr ) 2 ⎠ ⎜ W ⎟ ⎛ ω t dr ⎞ ⎝ ⎝ ⎠ ⎜ ⎜ 2 ⎟ ⎟ Where m is the analoge modulation index, f-dB ≈ 0.35/tr is ⎝ ⎠ bandwidth and tr is rise time. The term (4KBTf-dBFn/RL) is the Where ε is the material permittivity, tdr is the transit drift total noise associated with amplifier, it is referred to thermal time of carriers through the depletion region is: noise of load resistor RL by the amplifier noise figure Fn. t dr = W / 2υ d ( 37 ) For p on n devices where W is the width of the depletion region and υd is the average drift velocity of the carriers. In terms of measurable components Eq.37 The transit drift time IV. Results and Discussion becomes: Based on the above modeling equations analysis, the W 2 dynamic electro-optical characteristics of Si PIN photodiode t dr = ( 38 ) μ ( V + V bi ) are processed in high temperature gamma rays irradiations Where μ is the carrier mobility. fields. The double impact of thermal and radiation effects are The time for diffusion of carriers from the undepleted region analyzed over ranges of causes (affecting parameters). As to the depleted region is given by: 1012> γ, Fluence, e/cm2>1014 and 300>T, Temperature, l2 K>400. Special software programs are designed, cast and t Df = ( 39 ) employed to handle the given basic model, where variation of 2D set of electrical and optical devices parameters {ID, IP, α, η} Where D and l are the diffusion constant and the against variations of a set of two effects {T, γ} are processed. undepleted thickness, which changes with the changing of The device parameters are computed on bases of results of [5, the depletion layer width W. The time constant tRC of the 6, 18, 19, 20]. These variations will effect on response time tr, photodiode with a load resistance RL is given by: t RC = 2 . 2 (R S + R L ) C ( 40 ) responsivity S and signal to noise ratio SNR of the device. Based on the assumes set of the operating parameters, Where C is the capacitance of photodiode at applied bias V, and the equations analysis, then the obtained results are Rs is the series resistance of photodiode, it is the resistance displays in Figs. (1-7), for the processed Si device of optical of the contacts and the undepleted bulk of the substrate. wavelength of λ=950 nm are assured the following facts: ρ (W 0 − W ) RS = + contact resistore ( 41 ) A 0.75 0.7 Responsivity (A/W) 0.65 0.6 0.55 0.5 0.45 T=290 K T=330 K 0.4 T=370 K T=400 K 0.35 0.1 1 2 3 4 5 6 7 8 9 10 13 Fluence of Radiation (e/cm2) x 10 Fig. 1. Optical sensitivity of irradiated Si PIN photodiode at various radiation fluence and temperature. 271 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 -4 x 10 4.5 T=290 K 4 T=330 K Diffusion Length (m) T=370 K 3.5 T=400 K 3 2.5 2 1.5 1 0.5 0.1 1 2 3 4 5 6 7 8 9 10 13 Fluence of Radiation (e/cm2) x 10 Fig. 2. Diffusion Length of irradiated Si PIN photodiode at various radiation fluence and temperature. -11 x 10 4 T=290 K T=330 K 3.5 T=370 K T=400 K Drift Time (s) 3 2.5 2 1.5 0.1 1 2 3 4 5 6 7 8 9 10 13 Fluence of Radiation x 10 (e/cm2) Fig. 3. Drift Time of irradiated Si PIN photodiode at various radiation fluence and temperature. 4.5 T=290K Series Resistance (Ω) T=290K T=400K T=370K T=330K T=330K T=370K 4 T=400K 3.5 3 0.1 1 2 3 4 5 6 7 8 9 10 13 Fluence of Radiation (e/cm2) x 10 Fig. 4. Series Resistance of irradiated Si PIN photodiode at various radiation fluence and temperature. 272 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 -10 x 10 7.5 T=290 K Diffusion Time (s) 7 T=330 K T=370 K 6.5 T=400 K 6 5.5 5 4.5 4 0.1 1 2 3 4 5 6 7 8 9 10 13 Fluence of Radiation (e/cm2) x 10 Fig. 5. Diffusion Time of irradiated Si PIN photodiode versus radiation fluence and temperature. 3 Square Normalized Rise Time (-) * 2.8 Model * Expermental data 2.6 * 2.4 2.2 * 2 1.8 1.6 * 1.4 1.2 1 * 0.2 2 4 6 8 10 12 14 16 18 13 Fluence of Radiation (e/cm2) x 10 Fig. 6. Square rise time normalized to square rise time of unload Si PIN photodiode as function of radiation fluence. 13 T=290 K 12 T=330 K T=370 K T=400 K 11 SNR (dB) 10 9 8 7 0.1 1 2 3 4 5 6 7 8 9 10 13 Fluence of Radiation (e/cm2) x 10 Fig.7. Plot of SNR of irradiated Si PIN photodiode versus radiation fluence and temperature, m=0.3, Fn=3 dB, RL=50 Ω. i) As shown in Fig. 1 has assured that as fluence of radiation leads to increase in responsivity of device at constant on optoelectronic Si PIN device increases, this results in fluence of radiation. responsivity of device decreases at constant ambient ii) Fig. 2 has demonstrated that as fluence of radiation on temperature. But as ambient temperature increases, this optoelectronic Si PIN device increases, this results in 273 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 diffusion length of carriers decreases at constant ambient radiation defects. It is found that the degradation of device temperature. Moreover as ambient temperature increases, performance decrease with increasing irradiation temperature. this leads to increase in diffusion length of carriers at This result suggests that creation and recovery of the radiation constant fluence of radiation. damage proceeds simultaneously at high temperature degrees. iii) As shown in Fig. 3 has indicated that as fluence of radiation on optoelectronic Si PIN device increases, this REFERENCES results in drift time of carriers increases at constant ambient temperature. But as ambient temperature [1] Yu. K. Akimov, “Silicon Radiation Detectors: Instruments increases, this leads to decrease in drift time of carriers at and Experimental Techniques,” IEEE Trans. on Nucl. Sci., constant fluence of radiation. Vol. 50, No. 1, pp. 1–28, 2007. iv) Fig. 4 has proved that as fluence of radiation on [2] J.R. Srour, C. J. Marshall and P.W. 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Onoda, T. Hirao, J.S. Laird, H. Mori, T. Okamoto, Y. the dynamic characteristics of Si PIN photodiode under high Koizumi, and H. Itoh, “Spectral Response of a Gamma and temperature gamma radiation. The modeling basics yields an Electron Irradiated Pin Photodiode,” IEEE Trans. on Nucl. analytical expression for the responsivity of optoelectronic Sci., Vol. 49, No. 3, pp. 1446-1449, 2002. device as a function of irradiation Fluence and temperature. It [14] B. Danilchenko, A. Budnyk, L. Shpinar, D. Poplavskyy, is evident that also enable better prediction of photocurrent S.E. Zelensky, K.W.J. Barnham and N.J. Ekins, “1 MeV levels, delays and signal bandwidth. Moreover we have electron irradiation influence on GaAs solar cell demonstrated the circuit effects on signal performance that performance,” J. Solar Energy Materials and Solar Cells 92, included as a value of signal to noise ratio. The degradation pp. 1336– 1340, 2008. and delays can be explained by a decrease in the life time and [15] H. Ohyama, K. Takakura, K. Hayama, S. Kuboyama, Y. diffusion length of minority carrier caused by the formation of Deguchi, and S. Matsuda, E. Simoen and C. Claeys, 274 http://sites.google.com/site/ijcsis/ ISSN 1947-5500 (IJCSIS) International Journal of Computer Science and Information Security, Vol. 9, No. 5, May 2011 “Damage coefficient in high-temperature particle and γ- Author's profile irradiated silicon p–i–n diodes,” J. Appl. Phys. Lett., Vol. Dr. Ahmed Nabih Zaki Rashed 82, No. 2, pp. 296-298, 2003. was born in Menouf city, Menoufia State, [16] M. A. Cappelletti, A.P. C´edola1 and E.L. Peltzer y. Egypt country in 23 July, 1976. Received the Blanc´a, “Simulation of silicon PIN photodiodes for use in B.Sc., M.Sc., and Ph.D. scientific degrees in the Electronics and Electrical Communications space-radiation environments,” Semicond. Sci. Technol., Engineering Department from Faculty of Vol. 23, No. 2, pp. 7-13, 2008. Electronic Engineering, Menoufia University [17] J.R. Srour, Fellow and D.H. Lo, “Universal Damage Factor in 1999, 2005, and 2010 respectively. for Radiation-Induced Dark Current in Silicon Devices,” Currently, his job carrier is a scientific lecturer IEEE Trans. on Nucl. Sci., Vol. 47, No. 6, pp. 2451-2459, in Electronics and Electrical Communications 2000. Engineering Department, Faculty of Electronic [18] K. Takakura, K. Hayama, D. Watanabe, H. Ohyama, T. Engineering, Menoufia university, Menouf, Kudou, K. Shigaki, S. Matsuda, S. Kuboyama, T. postal Menouf city code: 32951, EGYPT. Kishikawa, J. Uemura, E. Simoen and C. Claeys, His scientific master science thesis has focused on polymer fibers in optical access communication systems. Moreover his scientific “Radiation defects and degradation of Si photodiodes Ph. D. thesis has focused on recent applications in linear or irradiated by neutrons at low temperature,” Physica B 376– nonlinear passive or active in optical networks. His interesting 377, pp. 403–406, 2006. research mainly focuses on transmission capacity, a data rate [19] H. Ohyama, T. Hirao, E. Simoen, C. Claeys, S. Onoda, Y. product and long transmission distances of passive and active Takami and H. Itoh, “Impact of lattice defects on the optical communication networks, wireless communication, radio performance degradation of Si photodiodes by high- over fiber communication systems, and optical network security temperature gamma and electron Irradiation,” Physica B and management. He has published many high scientific research 308–310, pp. 1226–1229, 2001. papers in high quality and technical international journals in the field of advanced communication systems, optoelectronic devices, [20] H. Ohyama, E. Simoen, C. Claeys, K. Takakura, H. and passive optical access communication networks. His areas of Matsuoka, T. Jono, J. Uemura and T. Kishikawa, interest and experience in optical communication systems, “Radiation damage in Si photodiodes by high-temperature advanced optical communication networks, wireless optical access Irradiation,” Physica E 16, pp. 533 – 538, 2003. networks, analog communication systems, optical filters and [21] S. M. Sze, Physics of Semiconductor Devices, John Wiley Sensors, digital communication systems, optoelectronics devices, & Sons, 3rd Ed, USA, 2007. and advanced material science, network management systems, [22] H. Li, “Refractive Index of Silicon and Germanium and Its multimedia data base, network security, encryption and optical Wavelength and Temperature Derivatives, Journal of access computing systems. He is a reviewer member in high quality Physical and Chemical Reference Data,” Vol. 9, No. 3, pp. scientific research international journals in the field of Electronics, Electrical communication and advanced optical communication 561−658, 1980. systems and communication access networks. His personal [23] J. Tauc, Amorphous and liquid semiconductors, New electronic mail (E-mail:ahmed_733@yahoo.com). York, Plenum Press, 1974. [24] Benjawan Kjornrattanawanich, Raj Korde, Craig N. Boyer, Glenn E. Holland, and John F. Seely, “Temperature Dependence of the EUV Responsivity of Silicon Photodiode Detectors,” IEEE Trans. on Electron Devices, Vol. 53, No. 2, pp.218-223, 2006. [25] Y. Pan, F. Inam, M. Zhang, and D. A. Drabold, “Atomistic Origin of Urbach Tails in Amorphous Silicon,” J. Physical Review Letters, Vol. 20, No. 6, pp. 1-4, 2008. [26] Martin A. Green, “Self-consistent optical parameters of intrinsic silicon at 300 K including temperature coefficients,” J. Solar Energy Materials & Solar Cells 92, pp. 1305– 1310, 2008. [27] K. Konno, O. Matsushima, D. Navarro, and M. Miura- Mattausch, “High frequency response of p-i-n photodiodes analyzed by an analytical model in Fourier space,” J. Appl. Phys., Vol. 96, No. 7, pp. 3839-3844, 2004. 275 http://sites.google.com/site/ijcsis/ ISSN 1947-5500

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Radiation effects, PIN photodiode, Optoelectronics, Transient current, Dark current, Photocurrent, Quantum efficiency, Responsitivity

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