1
GATE ECE 2014 Set 1
Numerical
+2
-0
A depletion type N -channel MOSFET is biased in its linear region for use as a voltage controlled resistor. Assume threshold voltage VTH = -0.5 V, VGS = 2.0 V, VDS = 5 V, W/L=100, COX=10-8 F/cm2 and $${\mu _n}$$ = 800 cm2/V-s. The value of the resistance of the voltage controlled resistor (in $$\Omega$$ ) is _____.
2
GATE ECE 2013
+2
-0.6
The small-signal resistance (i.e., $${{d{V_B}} \over {d{I_D}}}$$ ) in $$k\Omega$$ offered by the n-channel MOSFET M shown in the figure below, at bias point of VB = 2V is (device data for M: device transconductance parameter

kN = $${\mu _n}{C_{ox}^{'}}$$ (W/L)= 40$$\mu {\rm A}/{V^2},$$ threshold voltage VTN=1V, and neglect body effect and channel length modulation effects)

A
12.5
B
25
C
50
D
100
3
GATE ECE 2012
+2
-0.6
The source of a silicon (ni = 1010 per cm3) n - channel MOS transistor has an aewa of 1 sq $$\mu m$$ and a depth of 1 $$\mu m$$ . If the dopant density in the source is 1019/cm3, the number of holes in the source region with the above volume is approximately
A
107
B
100
C
10
D
0
4
GATE ECE 2012
+2
-0.6
In the three dimensional view of a silicon n-channel MOS transistor shown below, $$\delta = 20$$ nm. The transistor is of width 1 $$\mu m$$. The depletion width formed at every p-n junction is 10 nm. The relative permittivities of Si and SiO2, respectively, are 11.7 and 3.9, and $${\varepsilon _0}$$ = 8.9 $$\times {10^{ - 12}}$$ F/m.

The source-body junction capacitance is approximately

A
2 fF
B
7 fF
C
2 pF
D
7 pF
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