Drain current enhancement and negligible current collapse in GaN MOSFETs with atomic-layer-deposited HfO2 as a gate dielectric

作者：Chang Y C; Chang W H; Chang Y H; Kwo J^*; Lin Y S; Hsu S H; Hong J M; Tsai C C; Hong M

来源：Microelectronic Engineering, 2010, 87(11): 2042-2045.

DOI：10.1016/j.mee.2010.02.013

• GaN
• Metal-oxide-semiconductor field-effect-transistor (MOSFET)
• Current collapse
• HfO2
• Atomic layer deposition (ALD)

Accumulation-type GaN metal-oxide-semiconductor field-effect-transistors (MOSFETs) with atomic-layer-deposited HfO2 gate dielectrics have been fabricated; a 4 mu m gate-length device with a gate dielectric of 14.8 nm in thickness (an equivalent SiO2 thickness of 3.8 nm) gave a drain current of 230 mA/mm and a broad maximum transconductance of 31 mS/mm. Owing to a low interfacial density of states (DO at the HfO2/GaN interface, more than two third of the drain currents come from accumulation, in contrast to those of Schottky-gate GaN devices. The device also showed negligible current collapse in a wide range of bias voltages, again due to the low D-it, which effectively passivate the surface states located in the gate-drain access region. Moreover, the device demonstrated a larger forward gate bias of +6 V with a much lower gate leakage current.

• 出版日期2010-11
• 单位清华大学