Question

Consider an nMOS transistor in a 65 nm process with a minimum drawn channel
length of 50 nm (2= 25 nm). Let W/L = 4/2 1 (i.e., 0.1/0.05 um). In this
process,
the
oxide thickness is 10.5 Å. Estimate the high-field mobility of electrons to be 80
gate
cm?/V.s at 70 °C. The threshold voltage is 0.3 V. Plot Ids vs. Vas for Ves = 0, 0.2, 0.4, ,
0.6, 0.8, and 1.0 V using the long-channel model.
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Answer 1

problem has been solved

Answer 2

Consider an nMOS transistor in a 65 nm process with a minimum drawn channel length of 50 nm (λ = 25 nm). Let W/L = 4/2 λ (i.e., 0.1/0.05 um). In this process, the gate oxide thickness is 10.5 Armstrong. Estimate the high-field mobility of electrons to be 80 cm²/Vs at 70 °C. The threshold voltage is 0.3 V. Plot  $I_{ds}$ vs. $V_{ds}$ for $V_{gs}$ = 0,0.2, 0.4, 0.6, 0.8, and 1.0 V using the long-channel model.

Given:

High mobility field of electrons and oxide thickness.

To Find:

The plot of IV characteristics of an ideal $I_{ds}$ vs. $V_{ds}$ for $V_{gs}$

Solution:

Here according to the problem,

High field mobility,  µ = 80 cm²/Vs

Thickness, t = 10.5 Å

We first need to find β,

β = (W × 80 × 3.9 ×8.85 × 10⁻¹⁴)/ (L × 10.5 × 10⁸)

or, β= (262W × A)/(L × V²)

Now,

The figure shows the I-V characteristics of the nMOS transistor. According to the first-order model, the current is zero for gate voltages below $V_{t}$.

For higher gate voltages, the current increases linearly with $V_{ds}$ for small $V_{ds}$.

As $V_{ds}$ reaches the saturation point $V_{dsat}$ =$V_{GT}$, the current rolls off and eventually becomes Independent  $V_{ds}$ when the transistor is in saturation we will later see that the Shockley Model overestimates current at high voltages because it does not account for mobility. degradation and velocity saturation caused the high electric fields.

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