NOVEL INAS/(AL, GA)SB FET WITH DIRECT GATE-TO-CHANNEL CONTACT

A new type of FET has been fabricated in which the gate is in direct contact with the channel; there is no intervening charge separating layer. Instead, the separation of gate and channel carriers is achieved by using the staggered band alignment of InAs/(Al,Ga)Sb such that a p+ (Al, Ga)Sb gate layer is placed in direct contact with the n-type InAs channel. The absence of a gate insulator dielectric represents the ultimate in vertical device scaling. At 77 K the measured devices show both current gain and voltage gain, and a maximum transconductance of 500 mS/mm has been observed.