Influence of Gas‐Phase Stoichiometry on the Defect Morphology, Impurity Doping, and Electroluminescence Efficiency of Vapor‐Grown GaAs P‐N Junctions

Abstract

The vapor‐hydride method of epitaxial growth permits separate control of the flow rates of both the and HCl reactant species. In the present work, these variables have been independently adjusted to provide gas‐phase compositions ranging from Ga‐rich to As‐rich. The surface defect morphology has been found to be a strong function of the HCl flow rate, changing from pits at low flow rates to hillocks at higher flow rates. In contrast, the flow rate for constant HCl flows principally affects the size of the defects. The growth rate increases slightly with increasing flow rate, but decreases with increasing HCl flow rate over the range normally used. The Se‐donor and Zn‐acceptor concentrations both decrease with increasing HCl flow rate, suggesting that crystal stoichiometry is not strongly influenced by the HCl flow rate.Electroluminescent diode efficiencies range between 0.1 and 0.5% at room temperature and between 1 and 2.6% at 80°K. Peak efficiency values have been attained with slightly As‐rich gas‐phase conditions.