(e) An n-type In$_{0.53}$Ga$_{0.47}$As epitaxial layer doped at 10$^{16}$ cm$^{-3}$ is to be used as a channel in a FET operating at 300 K. A decision is to be made whether the JFET or MESFET technology is to be used for the device. In the JFET technology a p$^{+}$ region can be made with a doping of 5$\times$10$^{17}$ cm$^{-3}$. In the MESFET technology a Schottky barrier with a height of 0.4 V is available.
The materials parameters are:
$D_p$ = 20 cm$^2$/s, $D_n$ = 50 cm$^2$/s, $L_p$ = 5$\mu$m, $L_n$ = 5$\mu$m, $n_i$ = 2.37 10$^{11}$ cm$^{-3}$,
$A^*$ = 5 A cm$^{-2}$ K$^{-2}$.
(i) Calculate the reverse saturation current for JFET.
(ii) Calculate the reverse saturation current for the MESFET.
(iii) Considering gate isolation issues, which technology should be used?
