Hydride VPE Growth of GaAs for FET's

Epitaxial layers of GaAs suitable for fabrication of MESFET devices have been grown by the hydride VPE technique (AsH(3) + HCl + Ga + H(2)). The materials properties and FET characteristics of devices fabricated in this material are similar to those for LPE, and the more common AsCl(3) VPE growth techniques. The uniformity of sheet resistance of this material over a substrate area of similar to 6.5 cm(2) is typically,similar to 5% (standard deviation from the mean). A new technique has been developed for the growth of buffer layers. The background doping level of 4-9 X 10(15) cm(-3) is found to be reduced to <10(14) cm(-3) by the addition of NH(3) to the AsH(3) stream. More complex n(+)/n/buffer layer structures have been grown in a single operation by simply pro-gramming gas flow rates during the run.