Donor-acceptor interactions in Al0.5In0.5P

Abstract

INTRODUCTIONWide-bandgap III-V semiconductors, such as Al 0.5 In 0.5 P, are technologically important due to their common use as carrier-confining layers in various devices, including (Al x Ga 1Ϫx ) 0.5 In 0.5 P laser diodes and light emitting diodes. 1,2 In order to more effectively optimize the performance of such devices, it is, therefore, important to develop a more complete understanding of both n-type and p-type doping of such wide-bandgap semiconductors. Thus, any growth parameters or impurity species that alter donor or acceptor incorporation or diffusion properties may have important implications on device design, and it is, therefore, important to thoroughly understand such effects. With regard to such properties, we have previously demonstrated that the deep donor, oxygen, enhances Mg incorporation in Al 0.5 In 0.5 P. 3 Similar to our previous observations regarding Mg-oxygen interactions in Al 0.5 In 0.5 P, various other research groups have reported that shallow-donor species, such as S or Si, have enhanced acceptor incorporation in III-V semiconductors. [4][5][6][7][8][9][10][11][12][13] In addition to enhancing acceptor incorporation, such shallow-donor species have also been shown to suppress acceptor diffusion in III-V semiconductors, 4-13 thus providing motivation to investigate the potential impact of the deep donor, oxygen, on Mg diffusion in Al 0.5 In 0.5 P. In addition to this investigation of Mg-oxygen dopant interactions in Al 0.5 In 0.5 P, we also consider donor-acceptor interactions between Mg and the shallow donors, Te, S, and Si, to allow the reader to more effectively compare our results on Mg-oxygen dopant interactions to previous reports on dopant interactions between shallow donors and Zn or Mg acceptors. To the best of our knowledge, this paper offers the first detailed study of donor-acceptor interactions in Al 0.5 In 0.5 P, and it is also the first report we are aware of that compares the effect of deep-donor species to those of shallow-donor species on acceptor incorporation and diffusion in III-V semiconductors.In addition to the potential effect of oxygen on Mg diffusion in Al 0.5 In 0.5 P, such investigations of Mgoxygen dopant interactions may have major consequences on the growth of Al-bearing compounds, such as Al x Ga 1Ϫx As, Al 0.5 In 0.5 P, and perhaps AlGaN as well, where unintentional oxygen incorporation is often a source of concern. For example, Mg is known Dopant interactions are considered between Mg-acceptor atoms and various donor species, including the deep donor; oxygen; and the shallow donors, Te, S, and Si, in Al 0.5 In 0.5 P. While each of these donor species is shown to suppress Mg diffusion and enhance Mg incorporation in Al 0.5 In 0.5 P, careful analysis of the concentration profiles for these various donor species reveals subtle differences in the shape of the donor and acceptor dopant profiles, suggesting subtle differences in both the type of donor-acceptor interactions involved and in the effectiveness of the various donor species at suppressing Mg ...