OMCVD grown AlInAs/GaInAs HEMT's with AlGaInP schottky layer

The quality of undoped AlInAs is a key factor determining device performance of AllnAslGaInAs HEMT's. Recently the high background doping level of undoped AIMS grown by OMCVD has been a serious issue because it limits device performance of OMCVD grown AlInAs/GaInAs HEMT's. Very recently, the G ~ , L ~ I ~ P ternary material has attracted considerable interest as an alternative Schottky layer due to its wide band gap and absence of deep trap (e.g. DX centers) compared with AllnAs [1,2]. Furthermore, by adopting G a W as a Schottky layer, very uniform pinch-off voltage can be achieved using selective wet etching. However, the reported performance of LnGaAs HEMT's with GaInP Schottky layer are very poor. In this work, we have systematically investigated the device characteristics of AlMs/GaInAs HEMTs with (AI,Ga~,,)yIn~-yP as the Schottky layer.