Effects of substrate temperatures on the doping profiles of Si in selectively doped AlGaAs/GaAs/AlGaAs double-heterojunction structures

Abstract

Electrical properties of selectively doped double heterojunctions with a thin GaAs layer (≤300 Å) grown by molecular beam epitaxy are known to depend significantly on the substrate temperatures during growth. Although samples grown at 530 °C show high electron mobilities and reasonable electron concentrations, much lower mobilities and rather high electron concentrations have been obtained for those grown at 630 °C. Secondary ion mass spectrometry studies have been performed and have revealed that the degraded electrical properties are caused mainly by the surface migration of Si and the subsequent incorporation of Si into the undoped GaAs layer of the quantum well.