Please answer the following question: Syubject: semiconductor Physics: 4. (12 pt

Question

Please answer the following question:

Syubject: semiconductor Physics:

4. (12 pts) Multiple choice, choose one answer only for each part (you may mark your answer on this page and scan it if you wish) (3 pts) Constant field scaling is used in MOSFET technology to (choose I) a) Increase the size of transistors b) Increase the current of transistors c) Reduce transistor dimensions while keeping the power density constant d) Decreased frequency response a) b) (3 pts) Which of the following is NOT a short channel effect in MOSFETs (choose 1) ) Deceased current due to velocity saturation b) Threshold voltage shifts with gate length c) Increased hot electron damage in the oxide d) Increased breakdown voltage (3 pts) Which of the following is an effect associated with bandgap narrowing at high emitter doping (choose 1) a) Increased frequency response b) Increased current crowding c) Decreased emitter efficiency d) Improved Early voltage d) (3 pts) What is the benefit of using a Schotky-clamped BJT in circuit applications? (choose 1) a) Improved switching speed response for digital applications b)Improved common emitter gain c) Improved breakdown characteristics d) Improved Early voltage

Explanation / Answer

1. Constant field scaling gives reduction in power delay product of a single transistor. Which requires proportional reduction in power as size is deducted.hence anss is c.

2 .in MOSFET short channel effects are induced barrier lowering of drain, velocity saturation and hot Carrier degradation. So answer is b.

3 answer is heavy current crowding . Emitter band gap narrowing causes decrease in beta at high value of collector current which leads to current crowding

4.this transistor has a parallel diode to base collector terminals. Diode conducts at much lower forward bias than normal b-c junction which reduces time transistor to enter saturation mode. And also reduces turn off transient hence improved switching speed. Answer is 1

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