Growth and Implementation of Carbon-Doped AlGaN Layers for Enhancement-Mode HEMTs on 200 mm Si Substrates

We are reporting the growth of AlGaN based enhancement-mode high electron mobility transistors (HEMTs) on 200 mm silicon (111) substrates using a single wafer metalorganic chemical vapor deposition reactor. It is found that TMAl pre-dosing conditions are critical in controlling the structural quality, surface morphology, and wafer bow of the HEMT stack. Optimal structural quality and pit-free surface are demonstrated for AlGaN HEMTs with pre-dosing temperature at 750°C. Intrinsically, carbon-doped AlGaN, is used as the current blocking layer in the HEMT structures. The lateral buffer breakdown and device breakdown characteristics, reach 400 V at a leakage current of 1 μ A/mm measured at 150°C. The fabricated HEMT devices, with a Mg doped p -GaN gate layer, are operating in enhancement mode reaching a positive threshold voltage of 2–2.5 V, a low on-resistance of 10.5 Ω mm with a high drain saturation current of ~0.35 A/mm, and a low forward bias gate leakage current of 0.5 × 10 −6 A/mm ( V gs = 7 V). Tight distribution of device parameters across the 200 mm wafers and over repeat process runs is observed.