FORMATION OF HIGH-MOBILITY 2-DIMENSIONAL ELECTRON-GAS AT ETCH-REGROWN ALGAAS/GAAS INTERFACE PREPARED BY CHLORINE GAS ETCHING AND MBE IN AN UHV MULTICHAMBER SYSTEM

We demonstrate here that two-dimensional electron gas is successfully formed at the interface which is prepared by the Cl2 gas etching of MBE grown GaAs followed by the overgrowth of n-AlGaAs in an ultra-high vacuum multichamber MBE system. Electron mobility as high as 114,000 cm2/V-s at 9.8 K is achieved for the carrier concentration N(s) = 4.5 X 10(11) cm-2. The carbon incorporated at the interface is found to be a dominant additional scatterer for the electrons. It is shown that the carbon is incorporated mainly in the MBE chamber during the period of the sample transfer, and that the degradation caused by Cl2 etching itself is sufficiently small.