Study of GaInP/InGaAs linear graded Schottky barrier double channel heterostructure field-effect transistors (GDCHFETs)

Fabrications of GalnP/InGaAs linear-grade Schottky barrier double channel heterostructure field effect transistors (GDCFETs) are presented. The DC and RF characteristics of the studied devices with 1 and 0.8 mum gate length are compared and studied. By using the linear-grade Schottky barrier layer, the drawback of parallel conduction at high stress operation (especially at high gate voltage or high operation temperature) is eliminated. In addition, due to the employed InGaAs structure and Schottky behaviors of InGaP "insulator", good pinch-off and saturation characteristics, higher and linear transconductance, and good RF performances are obtained. The maximum transconductance is 218 mS/mm and 221 mS/mm for 1 mum and 0.8 mum gate length, respectively. The output current, defined at V
_Gs
=1.2 V is 380 mA/mm and 434 mA/mm for 1 and 0.8 mum gate length, respectively. High-speed device operation has been verified, with f
_T
of 15 GHz and f
_max
of 31 GHz for 1 and 0.8 mum gate length at room temperature. Therefore, the studied GDCHFETs provide the promise for high-temperature and high-performance microwave electronic applications.