Effect of interface properties on the characteristics of InP/GaInAs high electron mobility transistors

To overcome problems due to Al-containing layers the authors have developed a double heterostructure high electron mobility transistor (HEMT) design which only contains p- and n-doped InP and GaInAs. The layers were grown by low pressure metal organic vapor phase epitaxy (LP-MOVPE). These devices show very good performance. This material system suffers from problems with the abruptness of the interface. Therefore the effect of gas switching sequencies of the reactive gases was investigated using Raman spectroscopy. Based on these results a series of HEMTs was fabricated to investigate the impact of different interface configurations on device performance. It is shown that Hall mobilities of carriers, g_mext, f_T and I_DSS can be improved by a proper adjustment of gas switching sequencies