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+ (AI, 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. © 1991 IEEE