GaAs growth by atomic layer epitaxy using diethylgalliumchloride

Abstract

GaAs is grown by metalorganic atomic layer epitaxy (MOALE) using diethylgalliumchloride (DEGaCl) as a new MO source material for ALE and AsH3 in a horizontal, low-pressure metalorganic chemical vapor deposition system. Monolayer-unit growth has been obtained over a wide range of growth conditions, including growth temperature and the time of substrate exposure to DEGaCl. This ALE process is called ‘‘digital epitaxy,’’ and its advantages may be seen in its successful application here to extremely uniform GaAs growth on a 3-in. GaAs wafer. The digital nature of GaAs growth is well explained here using a Langmuir monolayer adsorption model for GaCl, a stable decomposition product of DEGaCl. Growth at higher temperatures leads to a reduction of carbon contamination; and at 600 °C, n-type layers with a 77 K mobility of 22 400 cm2/V s are obtained.