$($a$)$ A MOS device has a silicon dioxide insulator with a thickness of tox $20$ nm $200.$

$($i$)$ Determine the ideal breakdown voltage. $($ii$)$ If a safety factor of $3$ is required,

determine the maximum safe gate voltage that may be applied. $($b$)$ Repeat part

$($a$)$ for an oxide thickness of tox $8$ nm $80.$