Excellent-Performance AlGaN/GaN Fin-MOSHEMTs with Self-Aligned Al_2O_3Gate Dielectric

A1GaN/GaN fin-shaped metal-oxide-semiconductor high-electron-mobility transistors （fin-MOSHEMTs） with dif- ferent fin widths （30Ohm and lOOnm） on sapphire substrates are fabricated and characterized. High-quality self-Migned Al2O3 gate dielectric underneath an 80-nm T-shaped gate is employed by Muminum self-oxidation, which induces 4 orders of magnitude reduction in the gate leakage current. Compared with conventional planar MOSHEMTs, short channel effects of the fabricated fin-MOSHEMTs are significantly suppressed due to the tri- gate structure, and excellent de characteristics are obtained, such as extremely fiat output curves, smaller drain induced barrier lower, smaller subthreshold swing, more positive threshold voltage, higher transconductance and higher breakdown voltage.

Equivalent oxide thickness scaling of Al_2O_3/Ge metal-oxide-semiconductor capacitors with ozone post oxidation

Aluminum-oxide films deposited as gate dielectrics on germanium （Ge） by atomic layer deposition were post oxidized in an ozone atmosphere. No additional interfacial layer was electron microscopy and X-ray photoelectron spectroscopy detected by the high-resolution cross-sectional transmission measurements made after the ozone post oxidation （OPO） treatment. Decreases in the equivalent oxide thickness of the OPO-treated Al2O3/Ge MOS capacitors were confirmed. Furthermore, a continuous decrease in the gate leakage current was achieved with increasing OPO treatment time. The results can be attributed to the film quality having been improved by the OPO treatment.

Development and characteristic analysis of a field-plated Al_2O_3 /AlInN/GaN MOS-HEMT

We present an AIInN/AlN/GaN MOS-HEMT with a 3 nm ultra-thin atomic layer deposition （ALD） Al2O3 dielectric layer and a 0.3 μm field-plate （FP）-MOS-HEMT. Compared with a conventional AIInN/AlN/GaN HEMT （HEMT） with the same dimensions, a FP-MOS-HEMT with a 0.6 μm gate length exhibits an improved maximum drain current of 1141 mA/mm, an improved peak extrinsic transconductance of 325 mS/mm and effective suppression of gate leakage in both the reverse direction （by about one order of magnitude） and the forward direction （by more than two orders of magnitude）. Moreover, the peak extrinsic transconductance of the FP-MOS-HEMT is slightly larger than that of the HEMT, indicating an exciting improvement of transconductance performance. The sharp transition from depletion to accumulation in the capacitance-voltage （C-V） curve of the FP-MOS-HEMT demonstrates a high-quality interface of Al2O3/AlInN. In addition, a large off-state breakdown voltage of 133 V, a high field-plate efficiency of 170V/#m and a negligible double-pulse current collapse is achieved in the FP-MOS-HEMT. This is attributed to the adoption of an ultra-thin Al2O3 gate dielectric and also of a field-plate on the dielectric of an appropriate thickness. The results show a great potential application of the ultra-thin ALD-Al2O3 FP-MOS-HEMT to deliver high currents and power densities in high power microwave technologies.