Mg concentration profile and its control in the low temperature grown Mg-doped GaN epilayer. (January 2018) - Liu, S.T.
Abstract: In this work, the Cp2 Mg flux and growth pressure influence to Mg doping concentration and depth profiles is studied. From the SIMS measurement we found that a transition layer exists at the bottom region of the layer in which the Mg doping concentration changes gradually. The thickness of transition layer decreases with the increases of Mg doping concentration. Through analysis, we found that this is caused by Ga memory effect which the Ga atoms stay residual in MOCVD system will react with Mg source, leading a transition layer formation and improve the growth rate. And the Ga memory effect can be well suppressed by increasing Mg doping concentration and growth pressure and thus get a steep Mg doping at the bottom region of p type layer. Highlights: For first time we found that there exists a transition layer at the bottom region of p type GaN layer. We found that this transition layer is related to Ga memory effect which the Mg sources will react with Ga residual in MOCVD system. The Ga memory effect can be well suppressed by increasing Mg doping concentration and growth pressure and thus get a steep Mg doping at the bottom region of p type layer.