THEORETICAL AND EXPERIMENTAL RESULTS FOR THE INVERSION CHANNEL HETEROSTRUCTURE FIELD-EFFECT TRANSISTOR

New theoretical and experimental findings for the inversion channel HF ET are presented to address the modelling needs of inversion channel o pto-electronic integrated circuit (OEICs). This FET is well suited to OEICs since the gate is an ohmic contact (in contrast to a Schottky co ntact) controlling the channel conductivity from a substantial distanc e. Consequently, the region around the channel is formed as a graded i ndex structure with a single or multiple quantum well active region wh ich allows the FET to operate as a laser, a detector and an absorption modulator forming a complete component base for integration. It is sh own that the threshold voltage of this FET demonstrates unique depende ncies on charge sheet, barrier, and collector dopings, which allows wi de design flexibility and a substantially higher operating voltage tha n other III-V FETS. The effect of device length on threshold is examin ed experimentally and it is found that the gradient dV(TH)/dL may be p ositive or negative which raises the prospect that the condition dV(TH )/dL congruent-to 0 may be found to allow scaling to very small dimens ions. The device threshold and the bipolar injection from the gate con tact are controlled by a p contact to the collector region which serve s as an additional gate for the FET.