Question 6.2: For an n-​­channel MOSFET with a gate oxide thickness of 10 ...

For an n-​­channel MOSFET with a gate oxide thickness of 10 nm,V_{T} =0.6V, and Z = 25 µm, L = 1 µ m. Calculate the drain current at V_{G} =5VandV_{D} =0.1V. Repeat forV_{G} =3Vand V_{D} =5V. Discuss what happens forV_{D} =7V. Assume an electron channel mobility of \bar{\mu }_{n} =200 {cm^{2} }/{V-s}.

 

The blue check mark means that this solution has been answered and checked by an expert. This guarantees that the final answer is accurate.
Learn more on how we answer questions.
C_{i}=\frac{\epsilon _{i} }{d} =\frac{\left(3.9\right)\left(8.85\times 10^{-14} \right) }{10^{-6}} =3.45\times 10^{-7}{F}/{cm^{2} }

 

forV_{G} =5VandV_{D} =0.1Vand V_{T} =0.6V, V_{D}\lt \left(V_{G}-V_{T}\right), we are in the linear region. Thus,

 

I_{D}=\frac{Z}{L} \bar{\mu }_{n}C_{i}\left[\left(V_{G}-V_{T}\right)V_{D}-\frac{1}{2} V^{2}_{D} \right]

 

=\frac{25}{1}\left(200\right) \left(3.45\times 10^{-7} \right) \left[\left(5-0.6\right)\times 0.1 -\frac{1}{2}\left(0.1\right)^{2} \right] =7.51\times 10^{-4} A

 

forV_{G} =3Vand V_{D} =5V,V_{D} \left(sat.\right) =V_{G}-V_{T}=3-0.6=2.4V

 

I_{D} =\frac{Z}{L} \bar{u}_{n}[_{i}\left[\left(V_{G} – V_{T} \right)V_{D}(sat.)-\frac{1}{2}V^{2}_{D}\left(sat.\right) \right ]

 

=\frac{25}{1}\left(200\right)\left(3.45\times 10^{-7} \right) \left[\left(2.4 \right)^{2}-\frac{1}{2} \left(2.4 \right)^{2} \right] =4.97\times 10^{-3} A

 

For V_{D} =7V,I_{D} will not increase, because we are in the saturation region.

 

Related Answered Questions