Atomic layer-by-layer epitaxy of silicon and germanium using flash heating in CVD

Abstract

Atomic layer-by-layer epitaxy control of Si and Ge in flash-heating CVD using SiH 4 and GeH 4 gases was investigated. Self-limiting SiH 4 reaction on the Ge surface results in Si atomic-layer formation at substrate temperatures below 300 °C even without the flash heating. In the case of Ge growth, by increasing the flash light intensity and the GeH 4 partial pressure, Ge atomic-layer growth on the wet-cleaned Si(100) was achieved with a single flash shot at 275°C. Using these growth controls, resonant tunneling diodes of Ge/Si,Ge 1 (50A)/Ge(50A) / Si 1 Ge 1 (50A)/Ge, in which the Si 1 Ge 1 layers were formed by alternately depositing single atomic-layers of Si and Ge, were fabricated, and clear negative resistance in the current-voltage characteristic was observed at 10 K. The current peaks were expected to be assigned to a hole resonant tunneling via light-hole bound state in the Ge quantum well. This fact suggests that the diode structure has abrupt Si 1 Ge 1 /Ge interfaces by employing a low-temperature atomic layer-by-layer growth process below 300°C.