CHARGE STORAGE EFFECTS IN PSEUDOMORPHIC HIGH-ELECTRON-MOBILITY TRANSISTORS

We present for the first time results on charging effects in fully fab ricated pseudomorphic high electron mobility transistors (PHEMTs), usi ng in-situ, photoemission and conduction (PEC) studies. The experiment s were performed on GaAs based FETs with strained InGaAs channels. The se studies evaluate hole storage in the channel area which modifies th e threshold voltage of the field effect transistors (FETs). Deep level transient spectroscopy (DLTS) measurements were performed and the res ults compared to the data obtain from the photo studies. Understanding of hole storage is of significance in modeling the devices since hole s are attracted towards the channel when the device is pinched off.