Gallium nitride (GaN) and its allied binaries InN and AIN as well as their ternary compounds have gained an unprecedented attention due to their wide-ranging applications encompassing green, blue, violet, and ultraviolet (UV) emitters and detectors (in photon ranges inaccessible by other semiconductors) and high-power amplifiers. However, even the best of the three binaries, GaN, contains many structural and point defects caused to a large extent by lattice and stacking mismatch with substrates. These defects notably affect the electrical and optical properties of the host material and can seriously degrade the performance and reliability of devices made based on these nitride semiconductors. Even though GaN broke the long-standing paradigm that high density of dislocations precludes acceptable device performance, point defects have taken the center stage as they exacerbate efforts to increase the efficiency of emitters, increase laser operation lifetime, and lead to anomalies in electronic devices. The p...

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Luminescence properties of defects in GaN

Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.

A Survey of Wide Bandgap Power Semiconductor Devices

An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

and Perspectives Sophie Carenco,†,‡,§,∥,⊥ David Portehault,*,†,‡,§ Ced́ric Boissier̀e,†,‡,§ Nicolas Meźailles, and Cleḿent Sanchez*,†,‡,§ †Chimie de la Matier̀e Condenseé de Paris, UPMC Univ Paris 06, UMR 7574, Colleg̀e de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France ‡Chimie de la Matier̀e Condenseé de Paris, CNRS, UMR 77574, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Chimie de la Matier̀e Condenseé de Paris, Colleg̀e de France, 11 Place Marcellin Berthelot, 75231 Paris Cedex 05, France Laboratory Heteroelements and Coordination, Chemistry Department, Ecole Polytechnique, CNRS-UMR 7653, Palaiseau, France

Nanoscaled metal borides and phosphides: recent developments and perspectives

Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.

https://ieeexplore.ieee.org/ielaam/41/8031005/7815312-aam.pdf

Review of Silicon Carbide Power Devices and Their Applications

The stacking faults (SFs) in 4H-SiC epilayers have been characterized by microphotoluminescence spectroscopy and photoluminescence (PL) intensity mapping at room temperature. Three kinds of SFs, intrinsic Frank SFs, double Shockley SFs, and in-grown SFs, have been identified in the samples. Each kind of SF shows the distinct PL emission located at 420, 500, and 455nm, respectively. The shapes and distributions of SFs have been profiled by micro-PL intensity mapping. The formation mechanisms of each SF are also discussed.

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Characterization of stacking faults in 4H-SiC epilayers by room-temperature microphotoluminescence mapping

We report here 20-kV-class small-area (0.035 mm2) 4H-SiC bipolar junction transistors. We implemented edge termination techniques featuring two-zone junction termination extension and space-modulated rings. On-state characteristics showed a current gain of 63 and a specific on-resistance of 321 mΩ·cm2, which is slightly below the SiC unipolar limit. We achieved the open-base blocking voltage of 21 kV at a leakage current of 0.1 mA/cm2, which is the highest blocking voltage among any semiconductor switching devices.

21-kV SiC BJTs With Space-Modulated Junction Termination Extension

The temperature dependence of the refractive indices of GaN and AlN was investigated in the wavelength range from the near band edge (367 nm for GaN and 217 nm for AlN) to 1000 nm and the temperature range from room temperature to 515 °C. Optical interference measurements with vertical incident configuration were employed to precisely evaluate the ordinary refractive indices.

https://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/84572/1/326.pdf

The temperature dependence of the refractive indices of GaN and AlN from room temperature up to 515 °C

An edge termination method, referred to as space-modulated junction termination extension (SMJTE) combined with a mesa structure, is presented for ultrahigh-voltage p-i-n diodes in 4H-SiC. Numerical device simulations have been performed for over 15-kV-class 4H-SiC p-i-n diodes with the proposed edge termination. The structure exhibits a high breakdown capability with an improved tolerance for the deviation of impurity dose in the JTE region. Unlike conventional multi-implantation, the proposed termination technique utilizes a single-step implantation with a single mask. A desired laterally tapered doping profile is achieved by fragmenting a conventional JTE region using relatively wide spaces. The simple process of the proposed edge termination makes it applicable to fabrication of various high-voltage devices in 4H-SiC.

Space-Modulated Junction Termination Extension for Ultrahigh-Voltage p-i-n Diodes in 4H-SiC

The free hole concentration and the low-field transport properties of Al-doped 4H-SiC epilayers with several acceptor concentrations grown on semi-insulating substrates have been investigated in the temperature range from 100to500K by Hall-effect measurements. Samples have been grown by cold-wall chemical vapor deposition (CVD) in the Al acceptor concentration range from 3×1015to5.5×1019cm−3. The dependencies of the acceptor ionization ratio at 300K and the ionization energy on the acceptor concentration were estimated. Numerical calculations of the hole Hall mobility and the Hall scattering factor have been performed based on the low-field transport model using relaxation-time approximation. At the low acceptor concentrations, the acoustic phonon scattering dominates the hole mobility at 300K. At the high acceptor concentrations, on the other hand, the neutral impurity scattering dominates the mobility. A Caughey–Thomas mobility model with temperature dependent parameters is used to describe the dependen...

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Jun Suda

Papers

Characterization of stacking faults in 4H-SiC epilayers by room-temperature microphotoluminescence mapping

21-kV SiC BJTs With Space-Modulated Junction Termination Extension

The temperature dependence of the refractive indices of GaN and AlN from room temperature up to 515 °C

Space-Modulated Junction Termination Extension for Ultrahigh-Voltage p-i-n Diodes in 4H-SiC

Temperature and doping dependencies of electrical properties in Al-doped 4H-SiC epitaxial layers