Type conversion near the p-Si substrate surface by growing GaAs on Si substrates

Type conversion was observed near the p-type Si substrate surface by growing GaAs on the Si. Electron-beam induced currents and the spectral response of GaAs/Si solar cells indicated n-p junction formation in the Si near the interface. It was found that the type conversion was attributed not to As diffusion in the Si during the growth process, but to a positive interface charge in the GaAs/Si system. The interface charge density was estimated to be ≳8×1012 cm−2. Secondary-ion mass spectrometry depth profiles showed a certain amount of C accumulation at the interface, which had little effect on the type conversion.