Decoupling of epitaxy-related trapping effects in AlGaN/GaN metal–insulator semiconductor high-electron-mobility transistors

The decoupling of epitaxial factors influencing the dynamic instabilities of AlGaN/GaN metal–insulator semiconductor high-electron-mobility transistors is investigated. Three different sets of samples have been analyzed by means of dynamic instabilities in the threshold voltage (inline image shift). Secondary ion mass spectroscopy and steady-state photoluminescence (PL) measurements have been performed in conjunction with electrical characterization. The device dynamic performance is found to be significantly dependent on both the C concentration next to the channel, on the distance between the channel, and the higher doped C region. Additionally, we note that experiments studying trapping should avoid large variations in the sheet carrier density (inline image). This change in the inline image itself has a significant impact on the inline image shift. These experimental trends are also supported by a basic model and device simulation. Finally, the relationship between the yellow luminescence (YL) and the band edge (BE) ratio and the inline image shift is investigated. As long as the basic layer structure is not changed, the determination of the YL/BE ratio obtained from steady-state PL is demonstrated to be a suitable way to predict trap concentrations in the GaN channel layer