Kink phenomena in InAlAs/InGaAs HEMT's are investigated using a two-dimensional (2-D) device simulation that takes into account impact ionization, including nonlocal field effects, and the surface states in a side-etched region at the gate periphery. The simulation model enables us to represent the kink, and it is found that the accumulation of holes generated by the impact ionization has the channel electron density in the side-etched region increase at the bias point where kink appears. When the electron density in the side-etched region is small, the hole accumulation causes a significant increase in that electron density, resulting in a large kink. The simulation results suggest a model in which the kink is described in terms of the modification of the parasitic source resistance induced by the hole accumulation. This model implies a way to eliminate the kink, that is, keeping the electron density in the side-etched region high.
- Fet's, indium materials/devices
- MODFET's, semiconductor device modeling