Common Data Question 2, 3 and 4: The following figure shows the high-frequency capacitance-voltage (C-V) characteristics of a metal/SiO_2/silicon (MOS) capacitor having an area of 1 × 10^{−4} cm^2 . Assume that the permittivities (ε_oε_r) of silicon and SiO_2 are 1× 10^{−12} F/cm and 3.5 × 10^{−13} F/cm, respectively.
The gate oxide thickness in the MOS capacitor is
(a) 50 nm (b) 143 nm
(c) 350 nm (d) 1μm
The capacitance is given by
C=\frac{\varepsilon A}{d}
Therefore,
7 \times 10^{-12}=\frac{3.5 \times 10^{-13} \times 10^{-4}}{d}
where d is the gate oxide thickness (in cm). Therefore, d = 50 nm.
Ans. (a)