Schottky Barrier Formation on Electron Beam Deposited Amorphous Si1−xGex:H alloys and Amorphous (Si/Si1−xGex):H Modulated Structures

Abstract

ABSTRACTAmorphous Si:H and Si1−xGex:H films were prepared by mixing electron beam evaporated silicon with a molecular beam of germanium from a Knudsen cell and with a beam of ionized hydrogen produced by a 0–3 keV ion source. Aluminum Schottky barriers on two types of samples: (1) a-Si1−xGex:H with.15<×<.85 and (2) modulated structures of 50 × 100 Å layers of a-Si:H/a-Si.8Ge.2:H (10-5 Torr PH hydrogen) were investigated. Barrier height was found to depend on the Ge concentration and possible Fermi-level pinning due to the dangling bond deep level. The modulated structures showed a negative resistance region and a barrier height determined only by the composition of the first layer.