GaN and SiC Wafer Manufacturing Processes
Maurizio Di Paolo Emilio
Content Editor & Technical Writer | Ph.D | Power Electronics, Renewable Energy, Embedded Systems, Quantum Computing
GaN Wafers via FSB’s Technology
By Satya DIXIT
Gallium Nitride (GaN)?has become the de-facto material in 3rd generation Semiconductors. However, making GaN wafers in the quality you need and the?thermal resistance?you would desire are still the questions Fabs are trying to answer.
The mismatch of lattice constant and thermal expansion coefficient between GaN epilayers and substrates such as silicon, sapphire, and silicon carbide (SiC) lead to the generate dislocations and cracking of epi-layers.
The common method for thermal management is using substrates with high thermal conductivity, such as SiC or diamond as the heat sink. However, both the lattice mismatch and the coefficient of thermal expansion (CTE) mismatch between GaN and SiC/diamond make the heteroepitaxy very challenging. Furthermore, the conventional nucleation layer exhibits low thermal conductivity due to the defects and poor crystallinity. The thick buffer with low thermal conductivity would add significant thermal resistance to the heat dissipation path from the device to the substrate since most of the heat is generated within the active layer at the top. Defect and boundary scatterings within the transition layer, at the interface between the substrate and transition layer, and by near-interfacial disorder contribute together to large thermal resistance.
Improving the SiC Wafer Process
By Maurizio Di Paolo Emilio
The importance of silicon carbide in markets such as e-mobility and new energy has prompted many companies to review and invest in wafer technology to define development plans in line with the demand. X-Trinsic is a company that aims to improve the manufacturing process and focuses on accelerating the adoption of products in the SiC field as quickly as possible. X-Trinsic was founded by Dennis Ricco, CEO and EVP of customer operations, and Dr. Robert Rhoades, president and CTO, with the explicit purpose of providing services focused on the SiC market. These services fall into three categories:
In an interview with Power Electronics News, Dr. Robert Rhoades highlighted the steps of fabrication for SiC wafers and the importance of solid background knowledge for those working in this field, concerning not only electrical engineering but also materials science. “It’s critical to have a good, diverse team with the goal of understanding the properties of the material and how to design devices and circuits — and then systems — to be built with this unique material,” said Rhoades. “You need people who understand how to develop modules and systems and assemblies leveraging the properties of silicon carbide and the device’s characteristics in the best way at the system level. It’s very useful for engineers and technologists to have a broad broad perspective to understand the whole technology.”
SiC?demand is rapidly growing in three major markets: discrete power devices for energy efficiency (MOSFETs and diodes); power inverters and regulators (in electric vehicles, charging stations, data centers, wind and solar generators, etc.); and 5G communications (mobile phones and base stations which include both SiC devices and high-speed GaN-on-SiC devices).
AI-based GaN Epitaxial Wafer
By Maurizio Di Paolo Emilio
GaN?is?a?wide?bandgap?semiconductor?that?allows?devices?to?operate?at?higher?temperatures?and?with?higher?voltages?than?silicon. Furthermore, GaN’s stronger dielectric breakdown enables the construction of smaller and hence lower resistance devices. Smaller devices with less capacitance result from lower characteristic?Rds(on). IVWorks (South Korea), which uses deep learning-based artificial intelligence (AI) epitaxy technology to make gallium-nitride (GaN) epitaxial wafers, a key material in DC power devices and 5G communication devices, has secured $6.7 million in Series B investment.
Semiconductor Wafer Manufacturing with GaN
By RISE
领英推荐
Semiconductor wafers are used in almost all electronic products, including smartphones, computers, and automobiles. As the term indicates, a semiconductor is neither a conductor nor an insulator, but something in the middle. They can control how much current they conduct and thus adapt to each individual application.
Silicon?is?the?most?widely?used?semiconductor?material,?appearing?in?almost?every?electronic?device. It is indeed able to perform most tasks, at high temperatures or frequencies, but it may require the support of other semiconductor materials such as gallium nitride (GaN). Despite the fact that new materials are replacing silicon in some cases, silicon remains by far the most dominant semiconductor base material at the lowest cost. As a result, for next-generation semiconductor materials, a silicon wafer is frequently used as the base carrier material.
Silicon is produced in logs or cylinder-shaped “ingots” that are then sliced into very thin circular semiconductor disks, also known as wafers, that are often less than a millimeter thick. Electronic circuits can be defined or used as a base substrate for other semiconductor materials, such as GaN, on such a semiconductor wafer.
Expanding the SiC Wafer Supply
By Maurizio Di Paolo Emilio
The global race toward vehicle electrification is on, fueled by environmental concerns, state regulations, and consumer pressure.?Silicon carbide (SiC), a wide-bandgap semiconductor, has been a technology accelerator for?electric vehicles ?(EVs), as it increases the power density of the power-electronics subsystem while reducing its overall size, weight, and cost. Developers must meet the demands that require putting more people and goods into EVs while maintaining the vehicle’s size. For this reason, the market is moving toward reducing the size and weight of power-conversion equipment with SiC devices.
As the industry moves from internal combustion engines to EVs, the adoption of new solutions that can increase efficiency and offer longer range and faster charging will provide benefits across the powertrain, and device manufacturers want to ensure they have access to high-quality SiC substrates to support their customers.
Moving GaN Technology to the Next Stage
By Maurizio Di Paolo Emilio
Gallium nitride (GaN) is a?wide-bandgap?semiconductor material, which, compared with silicon, exhibits outstanding characteristics and performance, including high efficiency, high switching rate, excellent thermal management, and small footprint and weight. To achieve a large adoption of?GaN-based devices?in power applications, some barriers still need to be overcome, mainly related to its large-volume manufacturing and price reduction.?
GaN technology has evolved considerably over the years. Until around 2010, companies were busy in the R&D phase proving this innovative technology. The second phase, from 2010 to 2015, saw the first devices coming out in the market. This represented a big change that allowed people to buy GaN devices and start using them in real projects. Phase 3 began around 2015, when system engineers realized that GaN was not plug-and-play. They could not just replace silicon with GaN to get a better system; rather, they had to redesign their product to take advantage of GaN’s increased performance.?
Surface-Finishing Solutions Improve SiC Wafer Efficiency and Cost
By Maurizio Di Paolo Emilio
Semiconductors?are among the most widely used components in electronic circuits, in which they guarantee reliability, high resistance, and low cost. The manufacturing process of semiconductor devices, commonly used to create integrated circuits, involves a sequence of multiple photographic and chemical processing steps, during which the electronic circuits are gradually created on a wafer of pure?semiconductor material. Although silicon is still the most widely used semiconductor material, there are other semiconductors (such as wide-bandgap materials) that can offer superior performance to that of silicon.
Cover Image:?IVWorks