Thermal stability of base metal Cu/Ge metallized GaAs pHEMT

Authors: Erofeev E. V., Kazimirov A. I., Kagadey V. A.

Annotation: The article presents the results of thermostability research of GaAs pHEMT DC and RF parameters on the basis of Cu/Ge ohmic contacts and Ti/Mo/Cu gate and GaAs pHEMT completely executed on the basis of CuGe compounds. The transistor with complete Cu/Ge metallization and the gate length of a 170 nm had the maximal drain current of 560 mA/mm, a gate-drain breakdown voltage of 7 V, and transconductance maximum value of 380 mS/mm at UDS = 3 V. The maximum stable gain value was about 16,8 dB at frequency 10 GHz at current gain cut-off frequency of 80 GHz. Termostability tests of both types transistors were spent at temperature 250ºC during 120 min in a pure nitrogen environment. PHEMT with complete Cu/Ge metallization has greater thermostability of DC and RF parameters, than the transistor on the basis of CuGe ohmic contacts and Ti/Mo/Cu gate.

Keywords: gaas, phemt, cuge compounds, thermostability