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中国物理学会期刊

基于二次溅射的4H-SiC/Ti/TaSi2/Pt耐高温引线电极制备

CSTR: 32037.14.aps.74.20250801

Preparation of 4H-SiC/Ti/TaSi2/Pt high-temperature lead electrodes based on secondary sputtering

CSTR: 32037.14.aps.74.20250801
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  • 高温高压下硅基设备因自热效应漏电及形变, 无法长期稳定工作. 碳化硅作为第三代半导体在高温高频场景优势显著, 但其4H-SiC器件极限高温性能瓶颈源于欧姆电极与金属互连稳定性, 当前引线电极存在输出不稳定问题, 高温下氧气侵入易致输出失效. 研究在SiC/Ti/TaSi2/Pt欧姆接触基础上, 提出分批次溅射退火工艺制备耐高温引线电极, 通过改变退火与溅射顺序, 先在SiC衬底溅射Ti/TaSi2并退火形成欧姆接触, 再沉积Pt保护层, 构建新型SiC/Ti/TaSi2/Pt电极结构. 分批次溅射后退火形成的电极结构更致密, 600 ℃高温老化实验表明, Ti/TaSi2形成欧姆接触后溅射Pt的电极电学性能更稳定, 即初始比接触电阻率为6.35×10–5 Ω⋅cm2, 20 h空气老化后仍保持欧姆特性; Pt可有效抑制原子扩散和氧化反应使其电极微观形貌平整无卷曲. 分批次溅射退火工艺能显著提升SiC欧姆接触综合性能, 对其他金属组合欧姆接触的结构优化、稳定性提升及应用拓展具有重要指导意义, 为开发热稳定性强、适应复杂环境的欧姆接触提供思路.

     

    Under high temperature and pressure conditions, silicon-based devices experience leakage and deformation due to the self-heating effect, making them unable to operate stably for a long time. Silicon carbide (SiC), as a representative third-generation semiconductor material, is an ideal option for high-temperature, high-frequency, and high-power electronic devices. However, the high-temperature performance limitations of 4H-SiC devices stem from the stability of ohmic contact electrodes and metal interconnections. The output of the lead electrodes is unstable at present, and oxygen intrusion at high temperatures can easily cause output failures. Previous studies indicate that the SiC/Ti/TaSi2/Pt multilayer structure holds significant potential for ohmic contacts. Building upon this ohmic contact foundation, this study proposes a batch sputtering-annealing process to prepare high-temperature-resistant lead electrodes. This involves altering the sequence of annealing and sputtering: first sputtering Ti/TaSi2 onto the SiC substrate and annealing to form the ohmic contact, followed by depositing a Pt protective layer to construct a novel SiC/Ti/TaSi2/Pt electrode structure. Comparative analysis of the two experimental groups is conducted using scanning electron microscope (SEM), auger electron spectroscopy (AES), X-ray diffraction (XRD), thin-film stress measurement, and semiconductor analyzers. The batch-sputtered and annealed electrode structure can enhance density and reduce residual stress, with an initial specific contact resistivity of 6.35×10–5 Ω·cm2. High-temperature aging tests at 600 ℃ demonstrates superior electrical stability for electrodes formed by sputtering Pt onto Ti/TaSi2 after ohmic contact formation. These electrodes maintain ohmic characteristics even after 20-hour air aging, whereas traditional co-sputtered ohmic contacts transition to Schottky contacts. Pt effectively suppresses atomic diffusion and oxidation reactions, resulting in a smooth electrode microstructure without curling. The batch sputtering-annealing process not only greatly enhances the overall performance of SiC ohmic contacts but also provides crucial guidance for realizing the structural design and performance improvement of ohmic contacts by using other metal combinations. This approach holds significant reference value for the high-temperature packaging of third-generation semiconductor power devices and the development of electronic systems operating in harsh environments.

     

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