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Hiyoshi T.,Power Device Development Division | Masuda T.,Power Device Development Division | Wada K.,Power Device Development Division | Harada S.,Power Device Development Division | And 2 more authors.
SEI Technical Review | Year: 2013

SiC metal oxide semiconductor (MOS) devices are promising candidates for high power, high speed, and high temperature switches owing to their superior properties such as wide bandgap, high breakdown electric field, high saturation velocity and high thermal conductivity. However, the excellent device characteristics expected from these physical properties have not been realized, due to the issues related to SiO2/SiC interface. Although several methods to improve the interface state have been reported, the issues of SiO2/SiC interface have not been solved. In this paper, the authors improved the interface properties by using a 4H-SiC(0-33-8) face. The fabricated MOS field effect transistor (MOSFET) showed high channel mobility compared to the conventional crystal face (4H-SiC(0001)). In addition, the MOSFET showed a low on-resistance of 4 m cm2 with a blocking voltage of 890 V. Source

Hashimoto S.,Semiconductor Technologies RandD Laboratories | Akita K.,Semiconductor Technologies RandD Laboratories | Tanabe T.,Semiconductor Technologies RandD Laboratories | Nakahata H.,Semiconductor Technologies RandD Laboratories | And 2 more authors.
SEI Technical Review | Year: 2010

Epitaxial structures of aluminum gallium nitride (AlGaN) channel high electron mobility transistors (HEMTs) were grown on sapphire and aluminum nitride (AlN) substrates. Reduction in the full width at half maximum of X-ray rocking curve for (1012) peak of the AlGaN channel layer, owing to the reduction of threading dislocation density, resulted in a sharp decrease in the sheet resistance of 2-dimensional electron gas (2DEG). For AIGaN channel HEMTs, it was found that improvement of the crystalline quality of the AlGaN channel layers was essential to reduce the sheet resistance of 2DEG. The use of AlN substrates improved the crystalline quality of the AIGaN layer and lowered the 2DEG resistance. These results suggested the high potential of AlN substrates for AlGaN channel HEMTs. Source

Kyono T.,Semiconductor Technologies RandD Laboratories | Enya Y.,Semiconductor Technologies RandD Laboratories | Nishizuka K.,Semiconductor Technologies RandD Laboratories | Ueno M.,Semiconductor Technologies RandD Laboratories | And 2 more authors.
SEI Technical Review | Year: 2013

Optical characteristics of InGaN quantum wells (QWs) for green laser diodes on semi-polar {2021} GaN substrates were assessed using time-resolved photoluminescence (TRPL) and scanning near-field optical microscopy (SNOM). The InGaN QWs exhibited a remarkably shorter PL lifetime of 3.1 ns compared with that of conventional c-plane InGaN QWs, indicating that the piezoelectric fields are reduced greatly on {2021} planes. Furthermore, the characteristic energy E0 was estimated to be as small as 15.1 meV, which is less than one third of the reported value for c-plane InGaN QWs. Since E0 represents the localization depth in InGaN QWs, this result proves the high homogeneity of the In composition on {2021} planes. This conclusion was also verified by the spatially uniform distribution of the PL intensity and wavelength obtained by SNOM. These features are essential for highly efficient emissions in the green spectral region, consequently suggesting that the semi-polar {2021} plane is suitable for fabricating green laser diodes. Source

Takagi S.,Semiconductor Technologies RandD Laboratories | Ueno M.,Semiconductor Technologies RandD Laboratories | Katayama K.,Sumitomo Electric | Ikegami T.,Semiconductor Technologies RandD Laboratories | And 2 more authors.
SEI Technical Review | Year: 2013

The authors demonstrated InGaN green laser diodes (LDs) that were grown on semipolar {2021} GaN substrate and achieved output power of over 100 mW in the spectral region beyond 530 nm. In the range of 525-532 nm, these LDs realized wall plug efficiencies as high as 7.0-8.9%, which exceed those reported for c-plane LDs. Moreover, the InGaN green LDs are expected to have a long lifetime of over 5,000 hours under auto power control of 50 mW at a case temperature of 55°C. These results suggest that the InGaN green LDs grown on the {2021} plane are ideal as light sources for applications that require wavelengths of over 525 nm. Source

Sumiyoshi K.,Semiconductor Technologies RandD Laboratories | Okada M.,Semiconductor Technologies RandD Laboratories | Ueno M.,Semiconductor Technologies RandD Laboratories | Kiyama M.,Semiconductor Technologies RandD Laboratories | Nakamura T.,Semiconductor Technologies RandD Laboratories
SEI Technical Review | Year: 2013

Vertical gallium nitride (GaN) Schottky barrier diodes (SBDs) were fabricated on freestanding GaN substrates with low dislocation density. A high quality n-GaN drift layer with an electron mobility of 930 cm2/Vs was obtained under the growth condition optimized by reducing the intensity of yellow luminescence using conventional photoluminescence measurements. The concentration of impurities in the n-GaN drift layer was less than the detection limit of secondary-ionmass spectroscopy. The specific on-resistance (RonA) and the breakdown voltage (VB) of the SBDs were 0.71 mΩcm2 and over 1100 V, respectively. The figure of merit (VB2/RonA) was 1.7 GW/cm2, which is highest among previously reported SBDs for both GaN and SiC. With a forward current of 6 A at a forward voltage of 1.46 V and a breakdown voltage of 600V, the SBD with an electrode area of 1.1 x 1.1 mm2 demonstrated the possibility of application for power devices. Source

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