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

It is empirically known that the ON-resistance (voltage) of the SiC bipolar junction transistors (BJTs) with a thin-base layer is prone to be larger than the resistance of a voltage-blocking collector layer. In this paper, we explain the mechanism of this degradation of ON-characteristics by focusing on a high base spreading resistance and a parasitic diode existing below the base contact. An equivalent circuit model of the SiC BJT was proposed, and SPICE simulation was performed.In addition, TCAD simulation confirmed the validity of the model well. Based on the model, a design criterion to avoid the unwanted increase of the ON-resistance is proposed.

Design Criterion for SiC BJTs to Avoid ON-Characteristics Degradation Due to Base Spreading Resistance

The phonon dispersion carves for PbMoO 4 crystal were calculated on the basis of a rigid-ion model. The first-order Raman spectra of A g mode PbMoO 4 crystal were measured in a temperature range from 77 to 473 K. The temperature dependence of the linewidths was analyzed by using the phonon dispersion curves, and the results showed that it was caused approximately by the cubic anharmonic term in crystal potential energy. The temperature dependence of the frequency shift of the A g mode was analyzed by using the lattice dynamical perturbative treatment. We found that the quartic anharminic term of the first-order perturbation, as well as the cubic term of the second-order one contributes to the temperature dependence of the frequency shift of the A g mode in the PbMoO 4 crystal.

Lattice Dynamics and Temperature Dependence of the First-Order Raman Spectra for PbMoO 4 Crystal

In this letter we report optical properties of ZnSe/ZnMgSSe single quantum wells (SQWs) grown by metalorganic molecular beam epitaxy (MOMBE). At 4.2 K, a 10.5 monolayer (30 A) ZnSe SQW confined in Zn0.90Mg0.10S0.18Se0.82 layers exhibited intense purplish blue photoluminescence (PL) peaking at 2.865 eV, whose linewidth was as small as 5 meV. This emission was assigned to the n=1 heavy-hole exciton (E x1hh). Another peak appeared on the low-energy side of E x1hh under high excitation and grew nonlinearly with increasing excitation intensity. We tentatively attribute this line to the recombination of biexcitons. The exciton-longitudinal-optical(LO)-phonon coupling constant was also assessed from the temperature dependence of PL measurements.

Optical Properties of ZnSe/ZnMgSSe Single Quantum Wells Grown by Metalorganic Molecular Beam Epitaxy

The N2O-grown SiO2/4H-SiC (0001), (033¯8), and (112¯0) interface properties in p-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) have been characterized by using gate-controlled diodes. Although the inversion layer is not formed in simple SiC MOS capacitors at room temperature due to its large bandgap, a standard low frequency capacitance-voltage (C-V) curve can be obtained for the gate-controlled diodes, owing to the supply of minority carriers from the source region. From the quasistatic C-V curves measured by using gate-controlled diodes, the interface state density has been evaluated by an original method proposed in this study. The interface state density near the valence band edge evaluated by the method is the lowest at the oxides/4H-SiC (033¯8) interface. Comparison with the channel mobility is also discussed.

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N2O-grown oxides/4H-SiC (0001), (0338), and (1120) interface properties characterized by using p-type gate-controlled diodes

Scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) of a SiC multiple-pn-junction structure are presented. The structure was grown by atmospheric-pressure chemical vapor deposition using silane, propane and hydrogen. Nitrogen and diborane were used for n- and p-type doping gases, respectively. The SCM and SSRM results are compared with those of secondary ion mass spectrometry (SIMS). The 0.2-µm-thick n-type layer and 0.3-µm-thick p-type layer with a doping level of 1.5 ×1017 cm-3 in the multiple pn-junction were clearly resolved by both SCM and SSRM as well as SIMS.

https://iopscience.iop.org/article/10.1143/JJAP.41.L40/pdf

Jun Suda

Papers

Design Criterion for SiC BJTs to Avoid ON-Characteristics Degradation Due to Base Spreading Resistance

Lattice Dynamics and Temperature Dependence of the First-Order Raman Spectra for PbMoO 4 Crystal

Optical Properties of ZnSe/ZnMgSSe Single Quantum Wells Grown by Metalorganic Molecular Beam Epitaxy

N2O-grown oxides/4H-SiC (0001), (0338), and (1120) interface properties characterized by using p-type gate-controlled diodes

Scanning Capacitance and Spreading Resistance Microscopy of SiC Multiple-pn-Junction Structure