Power semiconductor devices are key components in power conversion systems. Silicon carbide (SiC) has received increasing attention as a wide-bandgap semiconductor suitable for high-voltage and low-loss power devices. Through recent progress in the crystal growth and process technology of SiC, the production of medium-voltage (600?1700 V) SiC Schottky barrier diodes (SBDs) and power metal?oxide?semiconductor field-effect transistors (MOSFETs) has started. However, basic understanding of the material properties, defect electronics, and the reliability of SiC devices is still poor. In this review paper, the features and present status of SiC power devices are briefly described. Then, several important aspects of the material science and device physics of SiC, such as impurity doping, extended and point defects, and the impact of such defects on device performance and reliability, are reviewed. Fundamental issues regarding SiC SBDs and power MOSFETs are also discussed.

https://iopscience.iop.org/article/10.7567/JJAP.54.040103/pdf

Material science and device physics in SiC technology for high-voltage power devices

A comprehensive introduction and up-to-date reference to SiC power semiconductor devices covering topics from material properties to applications Based on a number of breakthroughs in SiC material science and fabrication technology in the 1980s and 1990s, the first SiC Schottky barrier diodes (SBDs) were released as commercial products in 2001. The SiC SBD market has grown significantly since that time, and SBDs are now used in a variety of power systems, particularly switch-mode power supplies and motor controls. SiC power MOSFETs entered commercial production in 2011, providing rugged, high-efficiency switches for high-frequency power systems. In this wide-ranging book, the authors draw on their considerable experience to present both an introduction to SiC materials, devices, and applications and an in-depth reference for scientists and engineers working in this fast-moving field . Fundamentals of Silicon Carbide Technology covers basic properties of SiC materials, processing technology, theory and analysis of practical devices, and an overview of the most important systems applications. Specifically included are:

Fundamentals of Silicon Carbide Technology: Growth, Characterization, Devices and Applications

This survey deals with 1/f noise in homogeneous semiconductor samples. A distinction is made between mobility noise and number noise. It is shown that there always is mobility noise with an /spl alpha/ value with a magnitude in the order of 10/sup -4/. Damaging the crystal has a strong influence on /spl alpha/, /spl alpha/ may increase by orders of magnitude. Some theoretical models are briefly discussed none of them can explain all experimental results. The /spl alpha/ values of several semiconductors are given. These values can be used in calculations of 1/f noise in devices. >

1/f Noise Sources

Only a few years ago, an account of degradation of silicon carbide high-voltage p-i-n diodes was presented at the European Conference on Silicon Carbide and Related Compounds (Kloster Banz, Germany, 2000). This report was followed by the intense effort of multiple groups utilizing varied approaches and subsequent progress in both fundamental understanding of this phenomenon and its elimination. The degradation of SiC p-i-n junctions is now well documented to be due to the expansion of Shockley-type stacking faults in the part of the devices reached by the electron-hole plasma. The faults can gradually cover most of the junction area, impeding current flow and, as a result, increasing the on-state resistance. While in most semiconductors stacking faults are electrically inactive, in hexagonal silicon carbide polytypes (4H- and 6H-SiC) they form quantum-well-like electron states observed in luminescence and confirmed by first-principles calculations. The stacking-fault expansion occurs via motion of 30° sil...

Degradation of hexagonal silicon-carbide-based bipolar devices

Silicon carbide has attracted considerable attention in recent years as a potential material for sensor devices. This paper reviews the current status of SiC technology for a wide range of sensor applications. It is shown that SiC MEMs devices are well-established with operational devices demonstrated at high temperatures (up to 500 °C) for the sensing of motion, acceleration and gas flow. SiC sensors devices using electrical properties as the sensing mechanism have also been demonstrated principally for gas composition and radiation detection and have wide potential use in scientific, medical and combustion monitoring applications.

https://iopscience.iop.org/article/10.1088/0022-3727/40/20/S17/pdf

SiC sensors: a review

Simple analytical approximation has been obtained to describe the temperature and concentration dependencies of the low-field mobility in gallium nitride (GaN) in wide temperature (50⩽ T ⩽1000 K) and concentration (10 14 ⩽ N ⩽10 19 cm −3 ) ranges. The dependence of the temperature T m at which the mobility μ is at a maximum on the doping level is also obtained. Results obtained can be directly used for computer simulation of GaN-based devices.

Carrier mobility model for GaN

Local levels with a large activation energy E/sub a//spl sim/0.8-1.0 eV have been observed in low-frequency noise measurements of GaN/AlGaN heterostructure field effect transistors (HFETs and MOS-HFETs) grown on 4N-SiC substrates. The noise might come from the thin (30 nm) AlGaN barrier layer. The estimates of the level parameters based on this assumption resulted in reasonable values of capture cross section /spl sigma//sub n//spl ap/(10/sup -12/-10/sup -13/) cm/sup 2/ and trap concentration N/sub t//spl ap/5-10/sup 16/ cm/sup -3/.

Generation-recombination noise in GaN/AlGaN heterostructure field effect transistors

Low frequency noise has been investigated in gallium nitride/gallium–aluminum nitride GaN/GaAlN field effect transistors grown on sapphire and silicon carbide (SiC) substrates under identical conditions. GaN/AlGaN heterostructures grown on SiC substrate have a lower level of 1/f noise and a higher electron mobility compared to samples grown on sapphire. The noise of the gate leakage current Ig can give the main contribution to the output noise of the drain current Id even at Ig/Id ratios as small as 10−4–10−5. For the structures grown on SiC, a very weak temperature dependence of the low frequency noise was found in the temperature range 300 320 K. The effect of band-to-band illumination on the low-frequency noise is similar to that for silicon and gallium arsenide (GaAs) based transistors. The Hooge parameter α for the wafers grown on...

Low-frequency noise in AlGaN'GaN heterojunction field effect transistors on SiC and sapphire substrates

Sic Materials and Devices: Volume 1

The dependence of the base current gain β on the collector current IC has been measured in high-voltage 4H-SiC bipolar junction transistors at collector current densities jC from 20 to 700 A/cm2. With increasing collector current, the β value grows, reaching a maximum βmax=23 at j C max of about 250 A/cm2 and then decreasing sharply with further increase in current. The peculiarities of this dependence are analyzed in terms of a model taking into account the carrier recombination in the emitter space charge region (SCR), the surface recombination, and the emitter current crowding effect. It is shown that at relatively small jC the recombination in SCR plays a key role in limiting the β magnitudes. The decrease in β at high jC is mainly due to the surface recombination enhanced by the emitter current crowding effect. The effects of surface recombination and recombination in the SCR reduce the maximum current gain almost threefold: from 65 to 23.

Michael E. Levinshtein

Papers

Carrier mobility model for GaN

Generation-recombination noise in GaN/AlGaN heterostructure field effect transistors

Low-frequency noise in AlGaN'GaN heterojunction field effect transistors on SiC and sapphire substrates

Sic Materials and Devices: Volume 1

Factors limiting the current gain in high-voltage 4H-SiC npn-BJTs