In December 2017, the Shanghai Institute of Microtechnology and Photonics (SITRI), a leading research organization focused on "Beyond Moore" innovation platforms, launched the HV600/HV650 series of 8-inch silicon-based gallium nitride (GaN) epitaxial wafers designed for surface-to-air applications. These wafers are characterized by high crystal quality, excellent material uniformity, strong voltage resistance, and exceptional reliability. Notably, their effective lifespan exceeds one million hours, effectively addressing long-standing technical challenges in the application of silicon-based GaN materials. This breakthrough has enabled industrial adoption of medium- and high-voltage silicon-based GaN power devices.
Compared to traditional semiconductor materials, third-generation GaN offers significant advantages such as a wide bandgap, high saturation carrier velocity, high breakdown electric field, and superior thermal and radiation resistance. These properties make it ideal for next-generation high-speed and high-efficiency power devices. Its applications span wireless charging, fast charging, cloud computing, 5G communications, laser radar, and new energy vehicles, among others. Additionally, silicon-based GaN materials provide cost benefits, especially when using large silicon wafers as substrates, allowing manufacturing costs comparable to conventional silicon-based power devices. As a result, silicon-based GaN technology is increasingly seen as the mainstream in the field of new power electronics.
The Power Devices Division of SITRI was established in 2016 with the goal of developing silicon-based GaN materials for industrial use. At the Third National Symposium on New Semiconductor Power Devices and Application Technologies, Dr. Yuan Li, head of the division, presented the latest progress in SITRI’s 8-inch silicon-based GaN epitaxial material project. The HV600/HV650 series received widespread attention and high praise from industry professionals due to their high reliability and uniformity.
The epitaxial structure of the HV600/HV650 series is designed to align with 8-inch silicon process lines. By using low-resistance 8-inch silicon substrates and applying pre-strain technology, SITRI effectively addresses the thermal mismatch between silicon and GaN. The epitaxial layer structure is carefully selected based on specific application requirements.
Figure 1: Schematic diagram of the epitaxial structure of HV600/HV650 series materials.
The material quality of the HV600/HV650 series is outstanding. To meet the 600 V/650 V withstand voltage requirements, SITRI employs thick film epitaxial growth technology over 4 microns. Through optimized GaN epitaxial crystal growth control, issues like wafer warpage and crystal defects caused by lattice mismatch are effectively resolved. The HV600/HV650 series features crack-free surfaces, minimal warpage (≤ ±50 μm), and low surface roughness (≤0.3 nm), meeting the demands of mass production for 8-inch power devices.
Figure 2: Wafer warpage of HV600/HV650 series materials.
The defect density of the HV600/HV650 series is remarkably low. Using optimized GaN epitaxial defect control technology, the series achieves both high dislocation density and high crystal quality while maintaining high withstand voltage and thick film growth. The XRD (002/102) half-height widths are less than 400/500 arcseconds, respectively.
Figure 3: HV600/HV650 Series Material HRXRD GaN (002).
Figure 4: HV600/HV650 Series Material HRXRD GaN (102).
Material uniformity is another key strength of the HV600/HV650 series. The thickness of the 8-inch epitaxial layer and the Al variance of the AlGaN barrier layer are below 0.3% and 2%, respectively. This ensures high uniformity and yield in the mass production of large-size silicon-based GaN power devices, overcoming previous bottlenecks in industrial applications.
Figure 5: Epitaxial thickness distribution of HV600/HV650 series materials.
Figure 6: Al component distribution of AlGaN barrier layer in HV600/HV650 series materials.
For high-voltage applications at 600 V/650 V, the HV600/HV650 series demonstrates ample pressure resistance. Meeting strict industry standards for leakage current (1 μA/mm²), the vertical withstand voltage reaches 640/700 V. Under the same leakage current criterion of 0.1 μA/mm, the lateral withstand voltage is 700/760 V when the substrate is grounded and 950/1010 V when floating, fully meeting the needs of 600 V/650 V applications.
Figure 7: Vertical withstand voltage characteristics of HV600/HV650 series materials.
Figure 8: Transverse withstand voltage characteristics of HV600/HV650 series materials (substrate ground).
Figure 9: Transverse withstand voltage characteristics of HV600/HV650 series materials (substrate floating).
The forward conduction characteristics of the HV600/HV650 series are also impressive. The two-dimensional electron gas concentration exceeds 9×10¹² cmâ»Â², the mobility is greater than 1800 cm²/V·s, and the sheet resistance is below 400 Ω/sq.
Figure 10: Square resistance distribution of HV600/HV650 series materials.
Reliability is a key feature of the HV600/HV650 series. Based on optimized silicon-based GaN epitaxial growth technology, these materials have an effective life of more than one million hours (approximately 114 years) under nominal voltage conditions, as demonstrated through high-pressure TDDB testing.
Figure 11: Longitudinal high voltage TDDB test.
Additionally, the HV600/HV650 series exhibits excellent high-temperature performance. At 150°C with the substrate grounded, the lateral leakage for 600 V/650 V products is 0.7 and 0.6 μA/mm, respectively—both below 1 μA/mm. This ensures efficient and safe operation under typical power device temperature conditions.
Figure 12: Transverse voltage withstand characteristics of HV600 series materials at high temperature (substrate ground).
Figure 13: Transverse withstand voltage characteristics of HV650 series materials at high temperature (substrate ground).
The HV600/HV650 series of 8-inch silicon-based GaN epitaxial wafers developed by SITRI has overcome critical material bottlenecks in the mass production of silicon-based GaN devices. It marks a significant milestone in achieving industry-leading reliability with over one million hours of effective life. In addition, the series also includes smaller-sized epitaxial wafers such as 6-inch, meeting the diverse needs of the industry for silicon-based GaN epitaxial materials.
40L Agriculture Drone,Agricultural Spraying Drone,Drones Agriculture Sprayer,Agricultural Sprayer
Xuzhou Jitian Intelligent Equipment Co. Ltd , https://www.jitianintelligent.com