Investigation of mesa-sidewall effects on direct current and radio frequency characteristics of Ga_0.51In_0.49P/In_0.15Ga_0.85As/Ga_0.51In_0.49P pseudomorphic high electron mobility transistors

The influences and improved methods for mesa-sidewall effects of GaInP/InGaAs/GaInP pseudomorphic high electron mobility transistors are investigated and demonstrated. The mesa-sidewall effects of gate leakage current path and parasitic capacitance seriously degrade the device characteristics. For instance, the excessive gate leakage current, reduced breakdown voltage and transconductance, variation of threshold voltage, increased sidegating effect, and degraded radio frequency response are found when the number of the mesa sidewall is increased. In the work, a simple and low-cost technique of the selective removal of mesa-sidewall materials is introduced. This selective etching method can substantially eliminate the mesa-sidewall contact problems of heterostructure field-effect transistor devices. © 2000 American Vacuum Society.