Enhanced reliability of HEMT by using a TiN barrier

The use of Auger electron spectroscopy (AES) to explore the failure mechanism of high electron mobility transistors (HEMTs) subjected to high temperature storage (HTS) and operating life tests is discussed. Degradation at the early stage of HTS is associated with significant amounts of Ga and As outdiffusion through the ohmic areas. A TiN barrier placed between the AuGe/Ni/Au contact and the Ti/Pt/Au overlay metal is effective in eliminating this degradation and increasing the mean time to failure (MTTF) to >10/sup 8/ hours at 125 degrees C channel temperature.<
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