Threshold voltage in p-channel and n-channel mosfet

Question

1)i. Describe the defects of shift in threshold voltage in a p-channel and n-channel MOSFET.

ii. What are the causes of radiation hardening?

2) Write down the sources of oxide trapped charge? Describe how these charges can be a needed out.

3) Describe on the level 1 model parameters used in the SPICE circuit simulator.

4) Describe the sub threshold current model in level 3 SPICE model and derive the expression for Id in sub threshold region.

5) Explain the effects in a MOS transistor due to non-uniform doping.

6) Design the small signal model of the MOS transistor and deduce its different parameters associated with model.

7) Write brief notes on:

i. UMOS ii. VMOS iii. SEC IV. HMOS

8) Draw a resistance load inverter with R= 1KΩ such that Vol = 0.6. Enhancement type nMOS driver transistor has the parameters given below
V_DD = 5V  V_to=1V  γ= 0.2V1/2  μn cox =22μA/V²

Determine: (i) Aspect ratio w/l (ii) V_IL & V_IH (iii) Noise Margin