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BJT Processing

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					BJT Processing
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion
                                         n+ layer     p+ layer      n+ layer
4. Base p-type diffusion                                         p-base layer

5. Emitter n+ diffusion                             n+ buried layer

6. p+ ohmic contact
                                                                           p-substrate
7. Contact etching

8. Metal deposition and etching

9. Passivation and bond pad opening
BJT Processing
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion

4. Base p-type diffusion

5. Emitter n+ diffusion

6. p+ ohmic contact

7. Contact etching

8. Metal deposition and etching

9. Passivation and bond pad opening      p-substrate
BJT Processing
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion

4. Base p-type diffusion

5. Emitter n+ diffusion

6. p+ ohmic contact
                                            n epi layer
7. Contact etching
                                         n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                        p-substrate
BJT Processing




                                         p+ isolation layer




                                                                                       p+ isolation layer
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion

4. Base p-type diffusion

5. Emitter n+ diffusion

6. p+ ohmic contact

7. Contact etching
                                                              n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                                             p-substrate
BJT Processing




                                         p+ isolation layer




                                                                                         p+ isolation layer
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion

4. Base p-type diffusion

5. Emitter n+ diffusion

6. p+ ohmic contact
                                                                        p-base layer
7. Contact etching
                                                              n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                                               p-substrate
BJT Processing




                                         p+ isolation layer




                                                                                                     p+ isolation layer
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion

4. Base p-type diffusion

5. Emitter n+ diffusion
                                                              n+ layer                 n+ layer
6. p+ ohmic contact
                                                                                   p-base layer
7. Contact etching
                                                                         n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                                                           p-substrate
BJT Processing




                                         p+ isolation layer




                                                                                                       p+ isolation layer
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion

4. Base p-type diffusion

5. Emitter n+ diffusion
                                                              n+ layer     p+ layer      n+ layer
6. p+ ohmic contact
                                                                                      p-base layer
7. Contact etching
                                                                         n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                                                             p-substrate
BJT Processing
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion                      p+ isolation layer

4. Base p-type diffusion

5. Emitter n+ diffusion
                                         n+ layer     p+ layer      n+ layer
6. p+ ohmic contact
                                                                 p-base layer
7. Contact etching
                                                    n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                                        p-substrate
BJT Processing
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion                      p+ isolation layer

4. Base p-type diffusion

5. Emitter n+ diffusion
                                         n+ layer     p+ layer      n+ layer
6. p+ ohmic contact
                                                                 p-base layer
7. Contact etching
                                                    n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                                        p-substrate
BJT Processing
1. Implantation of the buried n+ layer

2. Growth of the epitaxial layer

3. p+ isolation diffusion                      p+ isolation layer

4. Base p-type diffusion

5. Emitter n+ diffusion
                                         n+ layer     p+ layer      n+ layer
6. p+ ohmic contact
                                                                 p-base layer
7. Contact etching
                                                    n+ buried layer
8. Metal deposition and etching

9. Passivation and bond pad opening                                        p-substrate
Doping Profiles in a BJT
Substrate PNP BJT
Lateral PNP BJT
Modifications to a BJT Process
 Dielectric isolation --- substrate isolation

 Superbeta transistors

 Double diffusion --- make acceptable JFETs

 Ion implanted JFETs --- make good JFETs

 Double diffused pnp BJTs --- make good pnp devices

				
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