Influence of the doping concentration on crystallographic pore growth on n-type InP and GaAs

The growth of crystallographical pores (crysto pores) in n-type InP and GaAs has been investigated in detail in this work. The dependence on several experimental parameters, like the substrate doping concentration N-D, the etching current density j, nucleation, and etching time lead to a large amount of data. It could be shown that the data can be consistently understood in the framework of a simple model for crysto pore growth developed earlier by the authors. The stochastic nature of the model allowed for its implementation into 3-dimensional Monte-Carlo simulations, which were already able to reproduce the major features of crysto pores, as well as many detailed results. In this framework, this work serves as expansion of the parameter space which is subjected to the simulations, since the aforementioned parameters serve as free input parameters for the simulations. First results indicate that the main model parameters, the branching probabilities at pore tips and walls (k(tips) and k(wall)) are higher for InP as compared to GaAs. This effect has been interpreted as caused by a stronger passivation of GaAs surfaces by HCl in comparison to InP. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim