碳化硅（SiC）材料具有卓越的宽禁带、高热导率和强大的耐压性能，SiC JBS二极管 具有高击穿电压、体积小、重量轻、关断速度快、导通压降低以及耐高温性能优越等特点， 被广泛应用于航天、高频整流、开关电源和保护电路等领域。因此，对于在高温、高压、 高湿以及大电流环境下使用的SiC JBS二极管，其可靠性对于保证稳定性和持久性有着严 格的要求。本文针对这一问题，对4H-SiC JBS 二极管在这些严苛环境下的可靠性进行了 深入的理论和实验探索。 第一，在175℃和反向偏置1200V的应力条件下进行多次测试，并借此分析了SiC JBS 器件在高温反偏条件下的退化机理。经过测试发现，器件在试验500小时后，击穿电压从 1596V 下降到1319V，在 1000小时后击穿电压上升至1615V。经分析，高温反偏下，温度 的升高导致了界面处能势垒的降低，激发了电子的热运动，使器件耐压能力降低。一部分 空穴在电场的作用下穿越4H-SiC与SiO2的界面，导致4H-SiC/SiO2界面处空穴浓度的增 加，在反向偏压作用下增加了隧穿的概率，导致击穿电压的增大。 第二，对SiC JBS二极管进行80%击穿电压的高温反偏应力考核和高温高湿反偏应力 考核进行对比试验。77颗样品均通过80%击穿电压的高温反偏应力试验，但是仅有18颗 通过高温高湿反偏应力，高温高湿反向偏压下器件的击穿电压大幅降低。 第三，对SiC JBS二极管施加重复浪涌电流波，研究重复浪涌对SiC JBS二极管的作 用机理，在2000次试验后，本文发现器件的正反I-V特性曲线均有退化，经分析可知，此 现象是由于器件的散热能力不够强，使迁移率降低，器件电参数发生退化。 第四，对SiC JBS二极管分别在室温（25℃）和175℃的条件下，施加逐步增大直至 器件被破坏的破坏性浪涌试验。器件随着温度变高，抗浪涌能力降低。经分析。浪涌电流 升高会使二极管的功率变大，导致结温上升，导通电阻增大，压降升高，超出4H-SiC JBS 二极管能够承受的温度极限，器件发生失效和损坏。 最后，本文对SiC JBS二极管进行温度循环试验和高压蒸煮试验。两项考核分别进行 1000 次循环和96小时，77颗被测器件全部通过。在温度循环试验中，最大VF、IR和BV 偏移分别仅为-1.3%、1.6×10-6μA和14V。通过Coffin-Manson模型预测实际使用寿命约为6.7 年。在高压蒸煮试验中，最大VF、IR和BV偏移分别为0.69%、4.3×10-6μA和51V， 击穿电压均有所上升。通过Hallberg Peck模型预测实际使用寿命约为16年。

Silicon Carbide(SiC)material has excellent wide bandwidth,high thermal conductivity and strong breakdown field performance, SiC JBS diodes combine the advantages of high voltage tolerance, fast switching of SBD diodes and low reverse leakage current of PiN diodes, and are widely used in aerospace, high-frequency rectification, switching power supplies and protection circuits. Therefore, for SiC JBS diodes used in high temperature, high voltage, high humidity and high current environments, their reliability has strict requirements for ensuring stability and durability. This paper addresses this issue by providing an in-depth theoretical and experimental exploration of the reliability of 4H-SiC JBS diodes in these harsh environments. Firstly, this paper conducts several tests under stress conditions of 175°C and reverse bias of 1200V, and uses this to analyse the degradation mechanism of SiC JBS devices under high temperature reverse bias conditions. After testing, it was found that the breakdown voltage of the device decreased from 1596V to 1319V after 500 hours of testing, and increased to 1615 V after 1000h. It was analysed that the increase in temperature under high temperature reverse bias led to a decrease in the energy barrier at the interface, which stimulated the thermal movement of electrons and reduced the device's ability to withstand voltage. A part of holes cross the interface between 4H-SiC and SiO2 under the action of electric field, leading to the increase of hole concentration at the interface of 4H-SiC/SiO2, which increases the probability of tunnelling under the action of reverse bias and leads to the increase of breakdown voltage. Second, in this paper, SiC JBS diodes were tested by high-temperature reverse bias stress at 80% of breakdown voltage and high-temperature and high humidity reverse bias stress for comparative tests. 77 samples passed the high-temperature reverse bias stress test at 80% of breakdown voltage, but only 18 samples passed the high-temperature and high humidity reverse bias stress, and the breakdown voltages of the devices under high-temperature and high humidity reverse bias were greatly reduced. Thirdly, this paper applies repetitive inrush current wave to SiC JBS diodes to study the mechanism of repetitive inrush on SiC JBS diodes. After 2000 tests, this paper finds that the forward and reverse I-V characteristic curves of the devices are degraded, which can be analysed to know that this phenomenon is due to the insufficiently strong heat dissipation ability of the devices, which reduces the mobility and the device electrical parameters are degraded. Fourthly, in this paper, destructive surge tests are applied to SiC JBS diodes at room temperature 25°C and 175°C, respectively, which gradually increase until the device is destroyed. The device's surge resistance decreases as the temperature becomes higher. Analysed. Elevated surge current leads to increased power and heat production in the diode, resulting in increased junction temperature, increased on-resistance, and higher voltage drop, which exceeds the temperature limit that the 4H-SiC JBS diode can withstand, and the device fails and is damaged. Finally, this paper carries out temperature cycling test and high voltage accelerated aging test on SiC JBS diodes. The two tests were conducted for 1000 cycles and 96 hours, respectively, and all 77 devices under test passed. In the temperature cycling test, the maximum VF, IR, and BV shifts are only -1.3%, 1.6×10-6μA, and 14 V. The actual service life is predicted to be about 6.7 years by Coffin-Manson model. In the high-voltage accelerated aging test, the maximum VF, IR, and BV shifts were 0.69%, 4.3×10-6μA, and 51V, respectively, and the breakdown voltages were all increased. The actual service life was predicted to be about 16 years by Hallberg Peck model.