1. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p-base layer n + layer p + layer

2. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate

3. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer n epi layer

4. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p + isolation layer

5. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p + isolation layer p-base layer

6. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p + isolation layer p-base layer n + layer

7. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p + isolation layer p-base layer n + layer p + layer

8. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p + isolation layer p-base layer n + layer p + layer

9. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p + isolation layer p-base layer n + layer p + layer

10. 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 8. Metal deposition and etching 6. p + ohmic contact 7. Contact etching 9. Passivation and bond pad opening p-substrate n + buried layer p + isolation layer p-base layer n + layer p + layer

11. Doping Profiles in a BJT

12. Substrate PNP BJT

13. Lateral PNP BJT

14. 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