AlInN/ GaN heterostructure field-effect transistors

摘要

We report on AlInN/GaN Heterostructure Field-Effect Transistors grown by MEMOCVD® technique [1] with virtually Ga-free AlInN layers. The layer thicknesses were 10 nm and 1 nm for AlInN and a thin AlGaN spacer layers, respectively. This technology allows for strain-free or strain-reduced structures for higher quality and performance nitride electronic devices. We obtained the two-dimensional electron gas (2DEG) sheet densities as high as 4.4×1013 cm-2, and our estimates show that even higher values (up to 6×1013 cm-2) might be achievable. The electron mobility was over 500 cm2/Vs. As seen from Figure 1, the thickness of AlInN layer controls the sheet 2DEG density and, therefore, 2DEG sheet resistance. This allows for fabrication on the same wafer normally-on and normally-off HFETs and MOSHFETs with low resistive gate-source and gate-drain access regions. The high sheet density allowed us to achieve a very low contact resistance (0.073 Ω-mm, see Figure 2). To the best of our knowledge this is the lowest contact resistance reported so far for GaN HFETs.