Defects divert current through unexpected channels, decreasing efficiency and heightening the risk of early device failure. Advanced epitaxial growth methods such as chlorine-based chemical vapor deposition enable precision-driven processes that aim to minimize defects from their inception.
SiC wafers of high quality are key components in creating a low-carbon power supply industry, according to IDTechEx’s recent research. SiC can enhance both efficiency and reliability in DC/DC boost converters used in electric vehicle (EV) charging systems.
High Breakdown Electric Field
SiC is a wide band-gap material, capable of withstanding voltage gradients eight times greater than silicon without succumbing to avalanche breakdown, making it suitable for high voltage power devices like diodes, power transitors and thyristors. Furthermore, SiC devices can be constructed using smaller device dimensions for reduced on resistance and overall system losses.
SiC’s exceptional breakdown electric field allows for the use of thinner drift regions, significantly decreasing on-state resistance per unit area and thus increasing switching speeds and improving overall efficiency.
Power electronics made of silicon carbide are increasingly being adopted across industries and applications, from industrial motor drives and renewable energy inverters to smart grid infrastructure and smart energy management devices. Their ability to handle higher voltages and faster frequencies has revolutionized power conversion technology.
High-Temperature Stability
Silicon carbide’s unique atomic structure makes it one of the most chemically and thermally stable materials on the market, making it suitable for high-powered applications operating at elevated temperatures. Thanks to this property, SiC power devices are increasingly being utilized.
Wide-scale production of SiC requires careful control of its physical vapor transport (PVT) growth process and quality of final SiC boule. Morphology of powder source material used, purity levels and polytype composition as well as size distribution all play important roles in PVT crystallization for high quality devices with no defects.
EAG laboratories possess extensive expertise in both bulk and spatially resolved analytic techniques for SiC. EBSD results show that both faces close to the Si substrate and growth face are single oriented (111). SIMS measurements show low concentrations of oxygen and nitrogen impurities.
Low Intrinsic Carrier Concentration
Silicon (Si) remains the material of choice for power electronics applications, yet is quickly reaching its operational temperature and voltage limits. Silicon carbide (SiC), on the other hand, offers an alternative with superior thermal and electrical properties – an appealing prospect when considering cost vs benefits of Si.
SiC is notable for its low intrinsic carrier concentration due to its unique hexagonal lattice of Si and C atoms.
SiC’s atomic structure also makes it one of the hardest and thermally stable semiconductor materials known. To produce optimal crystal quality necessary for high performance SiC devices, growth processes require high purity and stoichiometry levels to produce. Lower drain-source leakage current allows devices to function at higher temperatures without losing performance.
High Thermal Conductivity
SiC devices boast superior thermal conductivity (approximately three times that of silicon), dispersing heat efficiently to avoid hotspots that could reduce semiconductor device lifespan and performance degradation.
With increasing demands for more energy-efficient power systems, electric vehicles (EVs) and renewable energy solutions are in need of high-performing materials that can withstand increased voltage and temperature demands. Devices made out of SiC can help to increase EV driving range while simultaneously decreasing system losses.
Air Water’s advanced fabrication methods enable accurate control of impurities, providing quality 3C-SiC substrates. Their step-flow process minimizes defects while creating superior surface characteristics for epitaxial growth. Furthermore, our intentional doping with boron ensures lower concentrations of point defects (vacancies, oxygen and nitrogen) that contribute to bipolar degradation.
High Breakdown Voltage
SiC devices feature an exceptionally high breakdown electric field that enables them to withstand currents eight times greater than silicon or GaAs devices before experiencing an avalanche breakdown, significantly lowering voltage drop across devices and making possible smaller and more compact power semiconductor devices.
SiC’s relatively large band gap suppresses electron tunneling at the metal-semiconductor interface. Furthermore, its much lower impact ionization coefficient for electrons along 0001> than with silicon must play a major role in contributing to their higher critical electric field strength pn diodes.
SiC devices feature a much thinner blocking layer than Si devices at any given breakdown voltage, enabling higher majority carrier density in the n-layer and significantly reduced specific on-resistance, leading to higher power density and faster switching speeds. The reduction in device resistance allows for higher power density and faster switching.
High Current Density
SiC has an intrinsic carrier density much greater than silicon, leading to reduced on-state loss for power devices. Furthermore, SiC’s high thermal conductivity enables fast switching for various applications.
As is typical with new technologies, SiC devices initially come at an increased cost than their silicon equivalents. Nonetheless, manufacturers such as Wolfspeed and Arrow Electronics have made great strides toward lowering costs and simplifying design for these products.
As more people transition towards electric vehicles (EVs), reliability in power devices is of the utmost importance for their performance and lifespan. MOSFETs and FETs used in converters, inverters, battery chargers and motor control systems must provide reliable operations; SiC provides this reliability while simultaneously reducing power losses that lead to increased fuel efficiency for extended range.
High-Power Applications
SiC devices can handle high current densities while dissipating heat at a fraction of the cost associated with silicon devices, making them suitable for power applications. Their wider band gap also enables faster switching speed reducing power losses and increasing efficiency within devices such as FETs and MOSFETs.
SiC’s ability to withstand higher voltages than silicon allows it to withstand smaller form factor transistors and diodes to reduce battery management system weight and size in electric vehicles, thus shortening driving distances while still providing the energy necessary to charge their batteries.
Fundamental research conducted until 2004 on SiC epitaxial growth is reviewed in depth, including growth modes, rate determining processes, surface morphology characteristics and impurity doping during epitaxial growth.
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