Mass production-ready characteristics of AlGaN/AlN/GaN high-electron-mobility transistor structures grown on 200 mm diameter silicon substrates using metal-organic chemical vapor deposition

Mass production-ready technologies of AlGaN/AlN/GaN high-electron-mobility transistor (HEMT) structures on 200 mm diameter silicon substrates are developed using a large-scale metal-organic chemical vapor deposition system. High-yield epitaxial substrates on large-diameter wafers are required for reducing the cost of industrializing power device applications. Through multi-point vertical leakage current measurements, it was confirmed that the AlGaN/AlN/GaN HEMT, under optimum growth conditions, showed high yield characteristics such as a highly uniform leakage current and a low number of breaking points over the entire 200 mm diameter wafer. On introducing an AlN spacer layer between the AlGaN Schottky barrier and the GaN channel, a lower on-state resistance for power devices can be expected. Cross-sectional transmission electron microscopy images revealed that the thin AlN spacer layer was grown between the AlGaN and GaN layers with atomically abrupt and flat interfaces. HEMT structures with an AlN spacer layer exhibited a considerably high two-dimensional-electron-gas mobility of 2000 cm² V⁻¹ s⁻¹ at room temperature and 10 700 cm² V⁻¹ s⁻¹ at 77 K. The AlN spacer layer between the AlGaN and GaN layers was successfully fabricated and suppressed the alloy disorder scattering effect. (paper)