# Exercise 5.4-1

## All Quick Questions to

### 5. Integrated Circuits - Process Integration

| Basic Considerations for Process Integration
|  | Draw a cross section of an integrated pnp-bipolar transistor! Denote in the drawing all doping types and the purpose of the layers!
|  | Compare an integrated bipolar transistor made with or without an epitaxial layer. Describe advantages and problems of either approach.
|  | Give a plot of the doping atom concentration as a function of depth for the kind of transistor shown. Describe qualitatively but with rough numbers as far as possible Indicate the pn junctions in your drawing. Discuss their depth and distance in terms of process stability. Describe how the doping could be administered. Discuss possible problems encountered, in particular if the substrate doping is rather high. |  |
|  | What function has a "buried layer" in bipolar technology?
|  | Draw a cross section of two integrated p-MOSFET transistor! Denote in the drawing the materials and the purpose of the decisive layers! Include typical lateral and vertical dimensions! Give key requirements for the dielectrics!
|  | Give a schematic drawing of a two-level metallization; make a list of the essential process steps and enumerate the materials used in each step.
|  | What exactly is a field oxide needed for?
|  | What is the difference between MOS and CMOS? 'Compare a MOS and CMOS inverter for this.
|  | Draw a schematic cross-section of two complementary MOS transistors next to each other. Indicate the major difference to MOS.

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5.4 Summary to 5: Integrated Circuits - Process Integration

© H. Föll (Semiconductor Technology - Script)