GaAs/AlGaAs atomic layer epitaxy in a commercial MOCVD reactor

• Published in: Thin solid films Vol. 225; no. 1; pp. 105 - 108
• Main Authors: Liu, H., Zawadzki, P.A., Norris, P.E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 25.03.1993; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Surface and interface dynamics and vibrations; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Crystal growth; Thickness; Gallium Arsenides; Flux growth; Epitaxy; Aluminium Gallium Arsenides Mixed; Organometallic compound; Exposure time; Charge carrier concentration; Chemical vapor deposition
• DOI: 10.1016/0040-6090(93)90136-D
• ISSN: 0040-6090

Issues facing large area growth of GaAs by atomic layer epitaxy (ALE) are discussed. We have used a movable X-shaped mechanical barrier to divide the growth chamber into four zones. Alternate zones either supply source gas or mask the wafer from exposure to source gases. The substrate rotating beneath the barrier is alternately exposed to Group III and Group V sources. The thickness uniformity is affected by both the spatial variation of the TMG flux and the range of TMG flux in which self-limited growth is valid. Carbon incorporation can be reduced by using TBA and increasing TBA or AsH 3 exposure time. GaAs epitaxial layers with hole concentration lower than 10 17 cm −3 and thickness uniformity less than 2% over a 50 mm diameter wafer grown at 580 °C have been obtained. Preliminary 300 K photoluminescence measurement of ALE Al 0.34Ga 0.66As grown at 560 °C has shown strong emission intensity which compares with no emission from MOCVD AlGaAs grown at 560 °C.