Reliability of metal semiconductor field-effect transistor using GaN at high temperature

The reliability of a GaN metal semiconductor field-effect transistor (MESFET) was investigated. We used Au/Pt as a Schottky gate and Ti/Al as a source drain of a GaN MESFET. The thermal stress test of the GaN MESFET at high temperature was investigated. It was found that no change of FET characteristics was observed even after the device was heated at 400 degrees C for 1000 h. Furthermore, using a GaN MESFET which was heated at 400 degrees C for 1000 h, a life of FET at 350 degrees C was examined by a continuously current injection at 350 degrees C. We confirmed that the FET performance did not change at 350 degrees C for 150 h. No degradation of metal-semiconductor interface was observed by secondary ion mass spectrometry and a transmission electron microscope. The reliability of the GaN MESFET as a high-temperature operation transistor was fully demonstrated. (C) 1998 American Institute of Physics. [S0021-8979(98)03517-8].