Dry sequential process of photochemical etching and surface passivation of In0.52Al0.48As using HBr and H2S

Abstract

Articles you may be interested inPower loss measurements in quasi-1D and quasi-2D systems in an In 0.52 Al 0.48 As/In 0.53 Ga 0.47 As/In 0.52 Al 0.48 As heterostructure Reactive ion etch-induced effects on 0.2 μm T-gate In0.52Al0.48As/In0.53Ga0.47As/InP high electron mobility transistors J.Optimization of reactive ion etching of Al0.48In0.52As in CH4/H2 by the experimental design method In order to improve the Schottky diode characteristics of metal-In 0.52 Al 0.48 As, a new dry photochemical etching and sulfur passivation process has been developed. Excimer and deep UV lamps were used for photochemical etching and surface passivation, respectively. Auger electron spectroscopy measurement shows that this passivation process is as good as wet ͑NH 4 ͒ 2 S x and P 2 S 5 /͑NH 4 ͒ 2 S passivation in terms of sulfur coverage. Schottky diodes were fabricated on n-In 0.52 Al 0.48 As by electron beam evaporation of a multilayer metal contact of the form Mo/Ti/Pt/ Au ͑2/30/300/200 nm͒. The leakage current has been reduced by three orders of magnitude after applying this passivation process. X-ray photoelectron spectroscopy measurements illustrate that these free S* radicals are capable of replacing As-O and In-O bonds to As-S and In-S bonds. The conclusion is that the As-O and In-O bonds are the primary causes of leakage current. These bonds are dissolved after this photochemical sulfur surface passivation.

A near-field scanning optical microscopy study of the uniformity of GaAs surface passivation

“…4 Several characterization techniques have been used to probe the properties of the passivated surfaces. 5,6 The uniformity of passivation at submicron scale, however, has rarely been studied. As the device dimensions decrease to the nanoscale, the surface properties and uniformity of these properties at the submicron scale become increasingly important.…”