Peculiarities of Growing Multicomponent Solid Solutions by Pulsed Laser Depositation

Using the example of GaInAsP and GaInAsSbBi solid solutions grown on GaP substrates with crystallographic orientation (111), the features of pulsed laser deposition of multicomponent solid solutions based on group III–V compounds are studied. The solid solutions were chosen based on the indicated difficulties in growing by the method of pulsed laser deposition due to the fact that they consist of two group III metals and three highly volatile group V metalloids. Due to the relevance of their practical use for growing optoelectronic heterostructures by X-ray energy-dispersive microanalysis, scanning electron microscopy, and Raman scattering, an analysis of the composition of solid solutions and their morphology was carried out. It has been experimentally shown that the combination of an increase in the laser fluence and the addition of surface-active elements such as Bi or Sb to the composition makes it possible to reduce the droplet density on the surface of the grown film by three orders of magnitude, and reduce their average size from 300 nm to 45 nm. It was determined by X-ray energy-dispersive microanalysis that the droplets consist of indium. The main causes of stoichiometry violation are In droplets and partial desorption of V group elements. It has been established that the source of In droplets is the formation of a liquid fraction of In on the target surface during sputtering with a fluence of 2.3 J/cm2 and high surface diffusion of In from the bulk of the layer to the surface. It has been found that the introduction of surface-active elements into the composition of the solid solution leads to the prevention of desorption of highly volatile elements of the V group, for example, arsenic. It is shown that by increasing the laser fluence and selecting the composition of the solid solution, it is possible to improve the morphology of thin films grown by pulsed laser deposition.

GaP, pulsed laser deposition, solid solutions, GaP, semiconductors, group III–V compounds