Phase Diagram for Metalorganic Vapor Phase Epitaxy of Strained and Unstrained InGaAsP/InP

Abstract

The composition parameters x and y of In 1- x Ga x As y P 1- y /InP grown by low-pressure metalorganic vapor phase epitaxy (MOVPE) have been extracted from photoluminescence and X-ray diffraction by an iterative analysis using an improved gap energy function E g ( x , y ) with strain correction. These x and y values were confirmed by electron probe microanalysis. Phase diagrams (vapor-solid relations) between the input partial pressures of the precursors and x and y have been established, which are linear for both the group-III and group-V elements. These simple functions are very useful for practical applications. The temperature and pressure dependences of the ratios of the distribution coefficients k In / k Ga and k P / k As were measured for two different Ga precursors (TMGa and TEGa). The growth rate of InGaAsP was calculated as a function of composition, and good agreement with the measurements was found. An analysis of strongly strained (≤1.3%) InGaAsP layers shows that the above established function E g ( x , y ) and the vapor-solid relations are valid not only for nearly unstrained, but also for strongly strained compositions. The vapor pressure of TMIn was measured.