Flicker noise in GaN/Al/sub 0.15/Ga/sub 0.85/N doped channel heterostructure field effect transistors

We have investigated noise characteristics of novel GaN/Al/sub 0.15/Ga/sub 0.85/N doped channel heterostructure field effect transistors designed for high-power density applications. The measurements were carried out for various gate bias voltages V/sub GS/ and with the drain voltage V/sub DS/ varying from the linear to the saturation regions of operation V/sub DS/>5 V. Our results show that flicker, e.g., 1/f noise, is the dominant limiting noise of these devices; and the Hooge parameter is of the order of 10/sup -5/-10/sup -4/. The gate voltage dependence of 1/f noise was observed in the linear region for all examined V/sub GS/ and in the saturation region for V/sub GS/>0. These results indicating low values of the Hooge parameter are important for microwave applications.