Dow Corning Corp of Midland, MI, USA, which provides silicon and wide-bandgap semiconductor technology, has introduced a product grading structure for silicon carbide (SiC) crystal quality that specifies new tolerances on killer device defects, such as micropipe dislocations (MPD), threading screw dislocations (TSD) and basal plane dislocations (BPD). The new grading structure aims to optimize the range, performance and cost of next-generation power electronic device designs fabricated on Dow Corning's Prime Grade portfolio of 100mm SiC wafers, which it now offers in three new tiers of manufacturing-quality substrates labeled Prime Standard, Prime Select and Prime Ultra.
"Wide-bandgap semiconductor technology must deliver much more than high quality alone - it must deliver exceptional overall value," says chief technology officer Gregg Zank. "Our new SiC wafer grading structure meets this need head on," he adds. "It is the direct result of our close collaboration with the globe's leading power electronics device manufacturers, and aims to help give them what they need to quickly achieve their evolving design goals at an optimal price point."
Each successive Prime Grade wafer tier under Dow Corning's new product grading structure offers tighter tolerances for defect density and other critical performance properties that aims to allow users to precisely balance wafer quality and price, depending on the demands of their specific device applications. While many SiC substrate manufacturers promise low micropipe densities, Dow Corning claims to be the first to specify low tolerances of other killer defects, such as TSD and BPD. Such defects reduce device yields and inhibit the cost-efficient manufacture of large-area, next-generation power electronic devices with higher current ratings.
Dow Corning says that all 100mm Prime Grade SiC wafers offer consistent mechanical characteristics to ensure compatibility with existing and developing device fabrication processes. The portfolio includes:
Prime Standard, which guarantees MPD of 0.5cm-2?or less, offering an option for balancing performance and cost when designing simpler SiC power electronic components, such as Schottky or junction barrier Schottky diodes, with low to medium current ratings. Prime Select, which delivers more stringent tolerances for MPD (<0.2cm-2) and BPD (<800cm-2), suitable for more demanding SiC devices like pin diodes or switches. Prime Ultra, which enables the design of high-power devices that require the highest crystal quality. SiC substrates in this tier deliver extremely low MPD (<0.1cm-2), BPD (<500cm-2), TSD (<300cm-2) and a tightened wafer resistivity distribution for the design of the most advanced SiC power electronic devices, including next-generation switching devices like metal-oxide-semiconductor field-effect transistors (MOSFETs), junction gate field-effect transistors (JFETs), insulated-gate bipolar transistors (IGBTs) and bipolar junction transistors (BJTs) or pin diodes. In addition, the substrate quality can benefit high-voltage (3.3kV and higher) and high-current device designs.
"The precise tolerances defining each grade's crystal quality - coupled with Dow Corning's highly competitive pricing structure - reflect the company's deep familiarity with the competitive demands of the silicon semiconductors market," says Tang Yong Ang, vice president, Compound Semiconductor Solutions, Dow Corning. "Few competitors can bring Dow Corning's legacy of technological excellence, application expertise and collaborative innovation in silicon materials, and apply it to the development of next-generation compound semiconductor technology," he claims. "With the launch of this new wafer grading structure, we aim to provide SiC substrates that offer silicon-like quality and enable customers worldwide to compete and succeed in the fast-growing power electronics industry."
Prime Standard, Prime Select and Prime Ultra grades of 100mm SiC wafers are available globally from Dow Corning for development and sampling in standard production.
