HIGH PERFORMANCE REFRACTORY GATE SELF-ALIGNED GAAS MESFETS FABRICATED BY ARSINE AMBIENT RAPID THERMAL ANNEALING.

This technique has allowed the authors to take advantage of some of the strong points of rapid thermal annealing (RTA) for these devices without the difficulties of capped RTA or the uncertain As loss characteristics or uncapped or proximity RTA. Using this technique, self-aligned 0. 8-micrometer-gate-length MESFETs with 50-nm epitaxially-grown channels of 2 multiplied by 10**1**8/cm**3 nominal doping with minus 0. 14-V threshold voltage, k-factor as large as 590 mS/V-nm, maximum transconductance greater than 550 mS/mm, and greater than 350 mA/mm current drive capability have been fabricated. Fully ion-implanted devices have also been fabricated using arsine ambient annealing for both the channel and self-aligning n plus implant anneals. For **2**9Si 30-KeV channel implants and **2**9Si 40 KV self-aligning implants a k-factor as large as 610 mS/V-mm for a gate length of 0. 6 micrometer has been achieved. This k-factor is the largest reported for a GaAs MESFET.