GaAs MESFET with low current capability grafted onto quartz substrate

DC characteristics of a GaAs MESFET, which is grafted onto an optically flat quartz substrate, are presented and discussed. The authors utilized a GaAs MESFET having small current capability in order to avoid heat effects and to magnify the effects brought by transplantation. Improved pinch-off and saturation behaviours, as well as increased drain-gate breakdown voltage, stemming from the insulating property of the quartz substrate were observed. Negative shift of threshold voltage and degraded low-field mobility were also observed and both were attributed to the stresses acting on the active region.