1
GATE ECE 2017 Set 2
Numerical
+2
-0
A MOS capacitor is fabricated on p-type Si (silicon) where the metal work function is 4.1 eV and electron affinity of Si is 4.0 eV, Ec - EF = 0.9 eV; where Ec and EF are conduction band minimum and the Fermi energy levels of Si, respectively. Oxide$${\varepsilon _r} = \,\,3.9,\,\,\,{\varepsilon _{0\,\,}}=\,8.85 \times {10^{ - 14}}$$ F/cm, oxide thickness $${t_{ox}} = 0.1\,\mu m$$ and electronic charge q = $$1.6 \times {10^{ - 19}}$$ C. If the measured flat band voltage of the capacitor is –1V, then the magnitude of the fixed charge at the oxide semiconductor interface, in nC/cm2, is __________.
2
GATE ECE 2017 Set 1
Numerical
+2
-0
For the circuit shown, assume that the NMOS transistor is in saturation. Its threshold voltage Vtn = 1 V and its trans-conductance parameter $${\mu _n}{C_{ox}}\left( {{W \over L}} \right) = 1m{\rm A}/{V^2}.$$ Neglect channel length modulation and body bias effects. Under these conditions the drain current ID in mA is______.
3
GATE ECE 2016 Set 3
Numerical
+2
-0
Figures $${\rm I}$$ and $${\rm I}{\rm I}$$ show two MOS capacitor of unit area. The capacitor in Figure I has insulator materials X (of thickness t1 = 1 nm and dielectric constant $${\varepsilon _1}$$ = 4) and Y (of thickness t2 =3 nm and dielectric constant $${\varepsilon _2}$$ = 200). The capacitor in Figure $${\rm I}{\rm I}$$ has only insulator material X of thickness teq. If the capacitors are of equal capacitance, then the value of teq (in nm) is ______
4
GATE ECE 2016 Set 3
Numerical
+2
-0
In the circuit shown in the figure, transistor M1 is in saturation and has transconductance gm = 0.01 siemens. Ignoring internal parasitic capacitances and assuming the channel length modulation $$\lambda$$ to be zero, the small signal input pole frequency (in kHz) is _____