SELECTIVE AREA GROWTH OF GAAS AND ALGAAS WITH TMGA, TMAL, ASH3 AND HCL BY ATMOSPHERIC-PRESSURE MOVPE

To an increasing degree, modern concepts of integrated devices will make use of selectively deposited epilayers. The present paper describes the growth conditions and limitations for selective area epitaxy in the GaAs/AlAs material system using conventional MOVPE precursors and a controlled injection of HCl gas. For two representative, extreme Si3N4 mask to semiconductor surface relations, completely selective growth is achieved by optimizing the molar group-III and HCl flows. The homogeneous concentration and lateral distribution of the deposited material are highly influenced by the mask dimensions and different transport reactions or properties of the chlorides of gallium and aluminium. The morphology of the epilayers is determined by the typical slowly growing and nongrowing crystallographic planes. Their appearance and development depend on the alignment of the substrate windows and the individual surface kinetics and are described for different V/III ratios.