Normally-off p-GaN Gated AlGaN/GaN HEMTs Using Plasma Oxidation Technique in Access Region

Abstract

Normally-off p-GaN gated AlGaN/GaN high electron mobility transistors (HEMTs) were developed. Oxygen plasma treatment converted a low-resistive p-GaN layer in the access region to a high-resistive GaN (HR-GaN); that oxygen plasma treatment used an AlN layer as an oxygen diffusion barrier layer to prevent further oxidizing of the underlying AlGaN barrier layer, and to ensure that the low-resistive p-GaN layer in the access region was fully oxidized. Relative to conventional p-GaN gated AlGaN/GaN HEMTs, these AlGaN/GaN HEMTs with HR-GaN layers achieved a lower drain leakage current of 4.4 × 10 −7 mA/mm, a higher drain current on/off ratio of 3.9 × 10 9 , a lower on-state resistance of 17.1 •mm, and less current collapse. INDEX TERMS p-GaN gate HEMT, normally-off, high-resistivity GaN.

Thermal effect on dynamic R_on degradation of p-GaN AlGaN/GaN HEMTs on SiC substrates

“…In order to further investigate the traps mechanisms related to surface and buffer traps, different electrical parameters in the pulse-mode stress are discussed. Off-state drain voltage stress plays an important role in the degradation of dynamic on-resistance subjected to DC stress [10]. In this work, the relationship between dynamic resistance degradation and V DH of GaN-on-SiC are illustrated.…”

“…In recent years, the properties of wide-bandgap (WBG) materials, especially Gallium Nitride (GaN), have gained a lot of attention for high-power, high-frequency, and high-temperature application in the power and microwave range, because of large bandgap, high breakdown electric field, and high mobility two-dimension electron gas (2DEG) [1,2,3,4,5]. A p-type doped GaN layer is covered locally under the gate in order to achieve enough high threshold voltage with a low specific on-resistance [6,7,8,9,10]. However, the capabilities of a full integrated GaN power electronics are still limited by several reliability issues when GaN HEMTs are operated between kHz to MHz switching frequencies [11,12,13,14,15,16].…”

1.3 kV Vertical GaN-Based Trench MOSFETs on 4-Inch Free Standing GaN Wafer

“…Wide-bandgap GaN-based power devices have been regarded as the great potential candidates for the next generation efficient power electronics and compact power systems, owing to the superior material properties such as high electron mobility, large breakdown field strength and high thermal stability [ 1 – 5 ]. Compared with high electron mobility transistors (HEMTs) [ 6 – 11 ] and current aperture vertical electron transistors (CAVETs) [ 12 – 15 ], GaN-based trench metal oxide semiconductor field effect transistors (MOSFETs) [ 16 – 18 ] are more competitive to realize intrinsically normally-off operation with higher current density, lower specific on-resistance ( R on,sp ) and lower current collapse. Moreover, GaN-based trench MOSFETs possess relatively simple manufacturing process and do not need the regrowth of AlGaN/GaN layers [ 19 , 20 ].…”

Normally-Off p-GaN Gated AlGaN/GaN MIS-HEMTs with ALD-Grown Al2O3/AlN Composite Gate Insulator

“…However, to uniformly etch away the p-GaN in the non-gated access region and to overcome the plasma-induced damage during the p-GaN removal are extremely challenging tasks. Therefore, several teams are investigating the p-GaN etching process, such as etching stop technique [6], oxidation technique [7], and H plasma technique [8]. A positive threshold voltage can be obtained in HEMTs with p-type GaN layers, without affecting channel mobility; therefore, strategies involving the use of a p-type GaN layer are widely considered as the most effective among the strategies mentioned above.…”