Microwave performance of GaAs MESFET´s with AlGaAs buffer layers—Effect of heterointerfaces

Field-effect transistors consisting of GaAs active layers and Al0.33Ga0.67As buffer layers with abrupt, graded-bulk, and graded superlattice heterointerfaces were fabricated and compared to GaAs buffer transistors. Microwave measurements showed that a good interface is obtained in the graded superlattice interface structure and that there is a small improvement in gain (1-2 dB) over the GaAs buffer structure.