SiC MOSFET栅极氧化层缺陷检测
龚瑜，黄彩清
（深圳赛意法微电子有限公司，广东 深圳 518038）
摘 要 SiC以其耐高压，高频，高温和高功率密度的材料特性，广泛应用于高效电能转换领域。而其栅氧化层可靠性是评价器件可靠性的重要部分。本文根据SIC MOSFET结构特性和栅氧化层缺陷的形成机理，对一批应力筛选实验失效的样品进行研究，提出了一种针对SIC -MOSFET 的栅氧化层缺陷检测方法。方法使用了正面和背面失效EMMI定位了相同缺陷位置，同时利用聚焦离子束分析等方法找到了栅氧化层物理损伤点，对碳化硅晶圆级别异物缺陷完成了成分分析，验证了晶圆级栅极氧化层异物缺陷对于栅氧化层质量和可靠性的影响，对于SiC MOSFET的早期失效研究有着重要的参考作用。
关键词 碳化硅；晶圆缺陷；栅氧化层缺陷；高温栅偏实验
中图分类号：TN385；TN305；TG115.21+5.3 文献标识码：A doi:10.3969/j.issn.1000-6281.2024.02.009
Defect detection in oxidation layer of SiC MOSFET gate
GONG Yu，HUANG Caiqing
(Shenzhen STS Microelectronics Co. Ltd.，Shenzhen Guangdong 518038，China)
Abstract Silicon carbide MOSFETs are becoming an increasingly viable alternative to conventional silicon technologies. Although SiC MOSFETs are now commercially available, these devices still suffer from the low yield rate and reliability issue. These issues have been attributed to a large density of gate oxide and active defects in the SiO2–SiC interfacial region. The electrical characteristics of SiC MOSFET are strongly influenced by these defects because they affect the physical and electrical properties of the gate oxide interface. In this paper, the failure mechanism of the gated oxide defect under different particle locations with a commercial SiC power MOSFET device was analyzed. Frontside fault isolation and backside fault isolation method was proposed. Based on these results, a suspected hypothesis of fault isolation methods by electrical test was presented. The main failure mechanism of gated oxide defect in SiC MOSFET through case analysis was revealed, which has an important role in improving the efficiency of failure analysis.
Keywords silicon carbide；wafer defect；gate oxide defect；HTGB
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