Performance Enhancement in N2 Plasma Modified AlGaN/AlN/GaN MOS-HEMT Using HfAlOX Gate Dielectric with Γ-Shaped Gate Engineering

In this paper, we have demonstrated the optimized device performance in the Γ-shaped gate AlGaN/AlN/GaN metal oxide semiconductor high electron mobility transistor (MOS-HEMT) by incorporating aluminum into atomic layer deposited (ALD) HfO2 and comparing it with the commonly used HfO2 gate dielectric with the N2 surface plasma treatment. The inclusion of Al in the HfO2 increased the crystalline temperature (~1000 °C) of hafnium aluminate (HfAlOX) and kept the material in the amorphous stage even at very high annealing temperature (>800 °C), which subsequently improved the device performance. The gate leakage current (IG) was significantly reduced with the increasing post deposition annealing (PDA) temperature from 300 to 600 °C in HfAlOX-based MOS-HEMT, compared to the HfO2-based device. In comparison with HfO2 gate dielectric, the interface state density (Dit) can be reduced significantly using HfAlOX due to the effective passivation of the dangling bond. The greater band offset of the HfAlOX than HfO2 reduces the tunneling current through the gate dielectric at room temperature (RT), which resulted in the lower IG in Γ-gate HfAlOX MOS-HEMT. Moreover, IG was reduced more than one order of magnitude in HfAlOX MOS-HEMT by the N2 surface plasma treatment, due to reduction of N2 vacancies which were created by ICP dry etching. The N2 plasma treated Γ-shaped gate HfAlOX-based MOS-HEMT exhibited a decent performance with IDMAX of 870 mA/mm, GMMAX of 118 mS/mm, threshold voltage (VTH) of −3.55 V, higher ION/IOFF ratio of approximately 1.8 × 109, subthreshold slope (SS) of 90 mV/dec, and a high VBR of 195 V with reduced gate leakage current of 1.3 × 10−10 A/mm.

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Analysis of DC Characteristics in GaN-Based Metal-Insulator-Semiconductor High Electron Mobility Transistor with Variation of Gate Dielectric Layer Composition by Considering Self-Heating Effect

Applied Sciences ◽

10.3390/app9173610 ◽

2019 ◽

Vol 9 (17) ◽

pp. 3610 ◽

Cited By ~ 1

Author(s):

Hwang ◽

Jang ◽

Kim ◽

Lee ◽

Lim ◽

...

Keyword(s):

Leakage Current ◽

Dielectric Layer ◽

Gate Dielectric ◽

High Electron Mobility Transistor ◽

High Electron ◽

Gate Leakage Current ◽

Gate Leakage ◽

Metal Insulator ◽

Self Heating ◽

Dc Characteristics

This study investigates metal-insulator-semiconductor high electron mobility transistor DC characteristics with different gate dielectric layer compositions and thicknesses, and lattice temperature effects on gate leakage current by using a two-dimensional simulation. We first compared electrical properties, including threshold voltage, transconductance, and gate leakage current with the self-heating effect, by applying a single Si3N4 dielectric layer. We then employed different Al2O3 dielectric layer thicknesses on top of the Si3N4, and also investigated lattice temperature across a two-dimensional electron gas channel layer with various dielectric layer compositions to verify the thermal effect on gate leakage current. Gate leakage current was significantly reduced as the dielectric layer was added, and further decreased for a 15-nm thick Al2O3 on a 5-nm Si3N4 structure. Although the gate leakage current increased as Al2O3 thickness increased to 35 nm, the breakdown voltage was improved.

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Property of an AlGaN/GaN MIS Diode with Si3N4/Al2O3 Bilayer Gate Dielectric Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.815.30 ◽

2015 ◽

Vol 815 ◽

pp. 30-35

Author(s):

Ling Yan Shen ◽

Xin Hong Cheng ◽

Zhong Jian Wang ◽

Duo Cao ◽

Li Zheng ◽

...

Keyword(s):

Leakage Current ◽

Gate Dielectric ◽

Schottky Diodes ◽

Film Structure ◽

Dielectric Films ◽

High Electron ◽

Gate Bias ◽

Gate Leakage Current ◽

Gate Leakage ◽

2Deg Density

Metal-insulator-semiconductor (MIS) diodes with Si3N4/Al2O3 bilayer gate dielectric films deposited on an AlGaN/GaN heterostructure were fabricated, where the Si3N4 layer played a role of etching stopped layer to protect the Al2O3 film from being damaged. Compared with traditional Schottky diodes, a distinct suppression of gate leakage current was achieved for the MIS diodes both at forward and reverse bias, and the dominant leakage current mechanism is Fowler–Nordheim tunneling. The 2DEG density extracted from C-V curves was 3~7 ́1013cm-2, in the same order of magnitude as Schottky diodes and hall measurement. Although the existence of the bilayer dielectric did not affect the 2DEG density at the interface of AlGaN/GaN, Si3N4 layer shared more gate bias and led to more gate bias required to deplete 2DEG and turn down the devices, moreover, Si3N4 layer had no effect on suppressing the forward or reverse gate leakage current due to its narrow band gap width and band bending compared with a single Al2O3 film. The experimental results provided a reference for the design of gate dielectric film structure for AlGaN/GaN high-electron-mobility transistors (HEMTs).

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Influence of gate-leakage current on drain current collapse of unpassivated GaN∕AlGaN∕GaN high electron mobility transistors

Applied Physics Letters ◽

10.1063/1.1953873 ◽

2005 ◽

Vol 86 (25) ◽

pp. 253511 ◽

Cited By ~ 21

Author(s):

P. Kordoš ◽

J. Bernát ◽

M. Marso ◽

H. Lüth ◽

F. Rampazzo ◽

...

Keyword(s):

Leakage Current ◽

Electron Mobility ◽

Drain Current ◽

High Electron Mobility Transistors ◽

High Electron ◽

Gate Leakage Current ◽

Gate Leakage ◽

High Electron Mobility ◽

Electron Mobility Transistors ◽

Current Collapse

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Reduced gate leakage current and boron penetration of 0.18 μm 1.5 V MOSFETs using integrated RTCVD oxynitride gate dielectric

International Electron Devices Meeting 1998. Technical Digest (Cat. No.98CH36217) ◽

10.1109/iedm.1998.746475 ◽

2002 ◽

Author(s):

Hsing-Huang Tseng ◽

D.L. O'Meara ◽

P.J. Tobin ◽

V.S. Wang ◽

Xin Guo ◽

...

Keyword(s):

Leakage Current ◽

Gate Dielectric ◽

Gate Leakage Current ◽

Gate Leakage ◽

Boron Penetration

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AlGaN/GaN MIS-HEMT with PECVD SiNx, SiON, SiO2 as Gate Dielectric and Passivation Layer

Electronics ◽

10.3390/electronics7120416 ◽

2018 ◽

Vol 7 (12) ◽

pp. 416 ◽

Cited By ~ 11

Author(s):

Kuiwei Geng ◽

Ditao Chen ◽

Quanbin Zhou ◽

Hong Wang

Keyword(s):

Leakage Current ◽

Gate Dielectric ◽

Deep Trap ◽

Trap Density ◽

Interface Traps ◽

Gate Leakage Current ◽

Gate Leakage ◽

Metal Insulator ◽

Current Collapse ◽

Gate Leakage Current Density

Three different insulator layers SiNx, SiON, and SiO2 were used as a gate dielectric and passivation layer in AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMT). The SiNx, SiON, and SiO2 were deposited by a plasma-enhanced chemical vapor deposition (PECVD) system. Great differences in the gate leakage current, breakdown voltage, interface traps, and current collapse were observed. The SiON MIS-HEMT exhibited the highest breakdown voltage and Ion/Ioff ratio. The SiNx MIS-HEMT performed well in current collapse but exhibited the highest gate leakage current density. The SiO2 MIS-HEMT possessed the lowest gate leakage current density but suffered from the early breakdown of the metal–insulator–semiconductor (MIS) diode. As for interface traps, the SiNx MIS-HEMT has the largest shallow trap density and the lowest deep trap density. The SiO2 MIS-HEMT has the largest deep trap density. The factors causing current collapse were confirmed by Photoluminescence (PL) spectra. Based on the direct current (DC) characteristics, SiNx and SiON both have advantages and disadvantages.

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