Novel surface preservation technique for large area growth of (100) InP substrate by LPE

Abstract

The single most important factor in the fabrication and production of InP based optoelectronic devices is the materials to be used. In particular, the surface morphology of the epitaxially grown wafer is critical to the photolithographic process, and is a determining factor for the yield and ultimately, wafer and device production cost. In liquid phase epitaxy (LPE), defect-free growth of heterostructures on InP substrates is difficult to achieve due to the high vapor pressure of phosphorus which leads to the evaporation of phosphorus atoms from the surface of the substrate. This thermal decomposition causes the surface morphology of grown wafers to depart from the original mirror-like surface of the substrate. In this work, a novel surface preservation technique for large area growth of InP-InGaAs-InGaAsP heterostructures on InP substrate by LPE is described. Application of this technique has led to mirror-like surface morphology on wafers as large as two square inches.