Effect of ionized impurities at heterointerface on concentration and mobility of two-dimensional electrons in selectively doped heterojunction structures

• Published in: Japanese Journal of Applied Physics Vol. 33; no. 9A; pp. 4859 - 4862
• Main Authors: KADOYA, Y, NOGE, H, SAKAKI, H
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese journal of applied physics 1994
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Exact sciences and technology; Iii-v semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions; Physics; Aluminium arsenides; Two-dimensional systems; Gallium arsenides; Semiconductor materials; Impurity density; Ternary compounds; Theoretical study; Doped materials; Binary compounds; Silicon additions; Impurities; Ionization; Heterojunctions; Carrier mobility; Carrier density; Electron gas
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.33.4859

The concentration N S and the low-temperature mobility µ of two-dimensional electron gas in GaAs/AlGaAs selectively doped heterojunctions have been studied theoretically and experimentally for the case where ionized impurities are present at heterointerfaces. It is found that N S scarcely changes when the concentration N IF of interfacial impurities is below 1×10 11 cm -2 , but it rapidly disappears at higher values of N IF if the impurities are of the acceptor type. In contrast, the mobility is found to decrease substantially even when N IF is as low as 10 9 cm -2 . Based on these results, a quantitative guideline is drawn on the acceptable level of contamination in ultrahigh-vacuum wafer processings including molecular beam epitaxial regrowth.