Complete Qualification of an Electron Beam Gate PHEMT Process

High frequency power amplifiers have many commercial and military applications. A 0.18mum gate length power pHEMT process with individual source via (ISV) and 2 mil substrate thickness was developed for these applications. During the qualification of this process many reliability techniques such as FMEA, DPA, ESD, HAST, TC, and HTOL were used. Hot electron effect was also evaluated by both step stress and constant stress RF life tests. After resolving some initial test difficulties and improving process procedures, this process passed DPA, HAST and TC test. HBM ESD sensitivity level of 200V has been measured for a 300 mum FET, and HTOL test indicated a temperature related mean-time-to-failure (MTTF) of 3times10⁶ hour at a channel temperature of 125degC