AlN and AlGaN growth using low-pressure metalorganic chemical vapor deposition

In AlGaN growth using low-pressure metalorganic chemical vapor deposition the TMA-Bow-rate dependence and reactor-pressure dependence on the Al content were investigated. We found that the reduction of partial pressure of TMA is effective in preventing the reduction of the Al content. To apply AlN and AlGaN films to devices, we fabricated an insulated gate heterostructure field effect transistor (IG-HFET). The AFM image of 4 nm-thick AIN on GaN shows a rough surface composed of approximately 500 nm-size grains. The grain boundary may be the origin of the leakage current between gate and drain during the operation of the IG-HFET. Nevertheless, the device can operate with transconductance g(m) of 235 mS mm(-1) for L-g = 1.4 mu m. (C) 1998 Elsevier Science B.V. All rights reserved.