Criterion for the Stability Against Thermal Runaway During Blocking Operation and Its Application to SiC Diodes
Criterion for the Stability Against Thermal Runaway During Blocking Operation and Its Application to SiC Diodes
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DOI：
10.1109/jestpe.2016.2543526
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发表时间：
2016-09-01
影响因子：
5.5
通讯作者：
Kaminski, Nando
中科院分区：
文献类型：
--
作者：
Boedeker, Christian;Vogt, Timo;Kaminski, Nando
众所周知，硅肖特基二极管在高温和高阻断电压下阻断性能差。这种行为特别有问题，因为高漏电流[1]导致自加热，这进一步增加了泄漏。由于这种致命的反馈回路，可能会发生热失控[2]。碳化硅（SiC）器件被认为具有更低的漏电流水平和更好的热稳定性。然而，早期的SiC肖特基二极管受到非理想漏电流密度的影响[3]-[5]，因此也受到热失控的严重威胁。本文研究了商用SiC-Schottky和SiC-p-i-n二极管的阻断稳定性。由于SiC-Schottky和SiC-p-i-n二极管中不同的泄漏机制，这两种器件类型显示出不同的泄漏电流的电压和温度依赖性。然而，推导出的稳定性准则（SC）是一个合理的近似两种二极管类型。与SC一致，实验结果证明在高温操作期间甚至在最差的冷却条件下达到热稳定性。在规定的工作范围内，热失控不再是一个限制因素。然而，当达到SiC器件所承诺的更高电压、更高工作温度和更少冷却时，必须重新评估热失控的风险。
Silicon-Schottky diodes are well known for their poor blocking behavior at high temperatures and high blocking voltages. This behavior is particularly problematic, because the high leakage currents [1] lead to self-heating, which increases the leakage further. Due to this fatal feedback loop, a thermal runaway [2] may occur. Silicon carbide (SiC) devices are supposed to show much lower leakage current levels and a better thermal stability. However, early SiC-Schottky diodes were affected by nonideal leakage current densities [3]-[5] and, therefore, seriously threatened by thermal runaway as well. In this paper, the blocking stability of commercial SiC-Schottky and SiC-p-i-n diodes is investigated. Due to different leakage mechanisms in SiC-Schottky and SiC-p-i-n diodes, both the device types show different voltage and temperature dependences of the leakage current. Nevertheless, the derived stability criterion (SC) is a reasonable approximation for both the diode types. In agreement with the SC, experimental results prove that thermal stability is reached during high-temperature operation and even under worst cooling conditions. Within the specified operating range, thermal runaway is, thus, no longer a limiting factor. However, the risk of a thermal runaway has to be reassessed when going to higher voltage, higher operating temperatures, and less cooling as promised by the SiC devices.