High temperature performance measurement and analysis of GaN HEMTs

摘要

Objective of this paper is to evaluate the performance of GaN HEMTs for high temperature applications. A sample AlGaN/GaN HEMT structure is investigated using empirical data to evaluate the device performance at high temperatures. Input transfer and output characteristics are the key focus along with transconductance and saturation current. Intrinsic device parameters were calculated using measured S-parameter data at various frequencies under different bias conditions and temperatures. Transconductance found at 398 °K is 2.5 mS for the entire gate width. DC characteristics of the fabricated devices were examined at temperatures ranging from 295 °K to 363 °K. Maximum drain current measured at room temperature was 214 mA which reduced to 192 mA at 363 °K. Reduction in saturation drain current is found due to decrease in saturation carrier velocity and two dimensional electron density. Structure based simulation tool ATLAS from Silvaco Int. is used for numerical simulations. The simulated device performance is in good agreement with the empirical results. Experimental results for the critical parameters suggest that the device can operate in the GHz Range for temperature up to 600 °K. Further enhancement of the model device is suggested upon reviewing the measured results to improve the high-temperature performance.