Powdec K.k.

University of Sheffield

Hiroji Kawai

Shuichi Yagi

Sankara Narayanan Ekkanath Madathil

Akira Nakajima

Souta Matsumoto

Hironobu Narui

Fumihiko Nakamura

Shoko Echigoya

Yasunobu Sumida

This normally-off mode polarization super junction GaN-based FET has an undoped GaN layer, an AlGaN layer, an island-like undoped GaN layer, a p-type GaN layerand a p-type InGaN layerwhich are stacked in order. The FET has a gate electrodeon the uppermost layer, a source electrodeand a drain electrodeon the AlGaN layerand a p-type InGaN layerand a gate electrodewhich are located beside one end of the undoped GaN layeron the AlGaN layer. The gate electrodemay be provided on the p-type InGaN layervia a gate insulating film. At a non-operating time, n≤n<n<nis satisfied for the concentration nof the 2DEGformed in the undoped GaN layer/the AlGaN layerhetero-interface just below the gate electrode, the concentration nof the 2DEGjust below the gate electrode, the concentration nof the 2DEGin the polarization super junction region and the concentration nof the 2DEGin the part between the polarization super junction region and the drain electrode

Normally-off mode polarization super junction GaN-based field effect transistor and electrical equipment

This hetero-junction bipolar transistor includes a first n-type GaN layer, an AlGaN layer (0.1&#x2264;x&#x2264;0.5), an undoped GaN layer having a thickness of not less than 20 nm, a Mg-doped p-type GaN layer having a thickness of not less than 100 nm, and a second n-type GaN layer which are sequentially stacked. The first n-type GaN layer and the AlGaN layer form an emitter, the undoped GaN layer and the p-type GaN layer form a base, and the second n-type GaN layer forms a collector. During non-operation, two-dimensional hole gas is formed in a part of the undoped GaN layer near the hetero interface between the AlGaN layer and the undoped GaN layer. When the thickness of the p-type GaN layer is b [nm], the hole concentration of the p-type GaN layer is p [cm], and the concentration of the two-dimensional hole gas is P[cm], p&#xd7;b&#xd7;10+P&#x2265;1&#xd7;10[cm] is satisfied.

Hetero-junction bipolar transistor and electric device

Provided are a semiconductor device and a bidirectional field effect transistor which can easily overcome the tradeoff relation between the high voltage resistance and high speed in the semiconductor device using a polarization super junction, realize both the high voltage resistance and elimination of the occurrence of current collapse, operate at a high speed, and further the loss is low. The semiconductor device comprises a polarization super junction region and a p-electrode contact region. The polarization super junction region comprises an undoped GaN layer, an undoped AlGaN layerwith a thickness not smaller than 25 nm and not larger than 47 nm and 0.17&#x2264;x&#x2264;0.35, an undoped GaN layerand a p-type GaN layer. When the reduced thickness tR is defined as tR=u+v(1+w&#xd7;10) for the thickness u [nm] of the undoped GaN layer, the thickness v [nm] and the Mg concentration w [cm] of the p-type GaN layer, tR&#x2265;0.864/(x&#x2212;0.134)+46.0 [nm] is satisfied. The p-electrode contact region comprises a p-type GaN contact layer formed to be in contact with the p-type GaN layerand a p-electrode that is in contact with the p-type GaN contact layer.

Semiconductor device having a polarization super junction field effect transistor, electric equipment, bidirectional field effect transistor, and mounted structure body having the same

A low-loss GaN-based semiconductor device is provided. The semiconductor device has the InGaN layer (where 0&#x2266;z&#x3c;1), the AlGaN layer (where 0&#x3c;x&#x3c;1), the InGaN layer (where 0&#x2266;y&#x3c;1) and the p-type InGaN layer (where 0&#x2266;w&#x3c;1) which are sequentially stacked on a base substrate of a C-plane sapphire substrate, etc. At a non-operating time, the two-dimensional hole gas is formed in the InGaN layer in the vicinity part of a hetero-interface between the AlGaN layer and the InGaN layer, and the two-dimensional electron gas is formed in the InGaN layer in the vicinity part of a hetero-interface between the InGaN layer and the AlGaN layer.

Growing community of inventors

Oyama, Japan

Hiroji Kawai