Question $6(20$ marks$)$ oxide thickness is $\backslash (82\backslash$AA $\backslash ).$ Given that the flat band voltage, $\backslash (\backslash$mathrm$\{$V$\}\_\{\backslash$mathrm$\{$FB$\}\}\backslash )$ is $-0\mathrm{.}4$ V $,$ calculate at strong inversion

$($i$)$ the surface potential

$[4$ marks$]$

$($ii$)$ the maximum depletion layer width

$[2$ marks$]$

$($iii$)$ the gate voltage

$[4$ marks$]$

$($b$)$ Qualitatively explain how the oxide charges affect the threshold voltage.

$[4$ marks$]$

$($c$)$ List two differences between ionic, covalent and metallic bonds.

$[6$ marks$]$