## Solution for CMOS Digital Integrated Circuits Analysis and Design 3RD Edition Chapter 3, Problem 1

by Sung-Mo, Kang and Yusuf Leblebici
77 Solutions 13 Chapters 24439 Studied ISBN: 9780072460537 5 (1)

# Chapter 3, Problem Exercise_Problems 1 : 3.1 Consider a MOS system with the following...

3.1 Consider a MOS system with the following parameters:

a.  Determine the threshold voltage VT0 under zero bias at room temperature (T = 300 K).

Note that and .

b.  Determine the type (p-type or n-type) and amount of channel implant (NI/cm2) required to change the threshold voltage to 0.6V

## Step-By-Step Solution

3.1 Consider a MOS system with the following parameters:

a.  Determine the threshold voltage VT0 under zero bias at room temperature (T = 300 K).

Note that and .

SOLUTION :

First, calculate the Fermi potentials for the p-type substrate and for the n-type polysilicon gate:

The depletion region charge density at VSB = 0 is found as follows:

The oxide-interface charge is:

The gate oxide capacitance per unit area is calculated using the dielectric constant of silicon dioxide and the oxide thickness tox.

Now, we can combine all components and calculate the threshold voltage.

b.  Determine the type (p-type or n-type) and amount of channel implant (NI/cm2) required to change the threshold voltage to 0.6V

SOLUTION :

p-type implanted needed in the amount of: