Dielectric Thickness and Fin Width Dependent OFF-State Degradation in AlGaN/GaN SLCFETs

Accelerated OFF -State stressing of multichannel AlGaN/GaN Superlattice Castellated Field Effect Transistors (SLCFET) with varying dielectric thickness
$(d_{i})$
and fin-width
$(W_{fi n})$
was studied using noise measurements. As
$d_{i}$
increased, the failure mechanism changed from an abrupt breakdown to gradual time dependent dielectric breakdown (TDDB). Smaller
$W_{fi n}$
is found to extend lifetime compared to wider
$W_{fi n}$
under such stressing condition. Percolation theory and associated trap generation during stressing can explain the observed behavior.