Plasma etching of GaAs and InP using a CH4/H2 process gas and AlxGa1−xAs using a SiCl4 plasma are reported. Particular attention to etching characteristics as a function of gas and material composition, r.f. power, pressure and temperature are shown. Etching of GaAs and InP highlight two separate etching mechanisms. Surface roughness data at the etched surface is presented and Cl and CH4/H2 process chemistries are compared which shows the latter to yield significant improvements in etch surface characteristics.

We present a hybrid implant epitaxy process that alleviates the inherent depth-width-dependent limitation of ion implantation. This technique allows shallow implants, which produce a thin active N layer with a controlled doping gradient, to be buried at an arbitrary depth below the less-critical, epitaxiallygrown surface layer. The formation and characteristics of GaAs buried shallow-implant (BSI) layers for microwave power FETs will be discussed.

Spatially quantized systems of III–V compounds have, in recent years, attracted considerable theoretical interest. However, the fabrication of quantum dots, a three-dimensionally quantum-confined microstructure, is particularly cumbersome and requires sophisticated lateral patterning techniques. A method, reported recently, which utilizes the microporosity of Vycor brand porous glass to produce quantum-confined microcrystals of II–VI and IV–VI semiconductors, is now extended to the fabrication of III–V quantum dots, by incorporating a microwave plasma assisted MOCVD technique. In this process, organometallic precursors impregnated in porous glass can be effectively cracked to deposit III–V microcrystals in glass. The results are discussed in light of the quantum size effect manifested by the optical absorption and photoluminescence data.

Low energy ion damage effects have been investigated in GaAs-A1GaAs two dimensional electron gas (2DEG) materials. The effect of ion mass (He, Ar, Xe) and adsorbed C12 on the charge carrier density and mobility has been studied for ion bombarded 2DEG systems. The 2DEG mobility was significantly reduced by ion damage with the effect becoming more dramatic with smaller ion mass. For the same treatment, the two dimensional carrier density was relatively unaffected. The results of He ion exposure showed serious degradation of the 2DEG with moderate ion dose. Electrical measurements were performed to determine the conducting widths of narrow patterned wires. For the same structural widths (mask width) He defined wires showed smaller electrical widths than Ar milling in the presence of chlorine. Serious limitations to patterning small structures may be imposed using beam processes that include He or other light mass species.