Novel in situ optical monitoring method for selective area metalorganic vapor phase epitaxy

Abstract

A novel in situ optical monitoring method which we call feature scale interferometry (FSI) for selective area wetalorganic vapor phase epitaxy on masked substrates is described, and demonstrated on the growth of 2 μm wide GaAs wire structures. A beam of 488 nm Ar+ laser light irradiated a GaAs (001) surface covered with a mask having line and space patterns during growth. In this technique the reflected light intensity decreases and displays oscillatory behavior as the growth proceeds, due to the interference between the reflected light from the top of the wires with trapezoidal cross sections and that from the masked areas of the substrate. From the peak and the valley positions in the reflected light intensity, we can estimate the growth thickness of the wire structures. Thicknesses measured using FSI agree well with those obtained from cross-sectional scanning electron microscopy.