Abstract Prior work has shown that the OFF-state breakdown voltage, VBR, of AlGaN/GaN high electron mobility transistors (HEMTs) can be raised by just extending the drain end of the gate as a field plate (FP) or a high-k passivation over the AlGaN layer. However, the two techniques have not been compared, and the VBR for which their effectiveness was demonstrated was ≥120 V. High-k passivation avoids the lithography involved in realizing a FP, and the VBR of practical devices can go down to a few 10's of volts. Hence the present work compares the effectiveness of these techniques by TCAD simulations and establishes the following. At VBR of few 10's of Volts, the high-k passivation is much less effective than the FP, e.g. for a device with VBR = 28 V, a 0.7 μm long FP over 0.105 μm thick SiN doubles the VBR to 56 V, whereas even a 0.5 μm thick HfO2 passivation (er = 20) has almost no effect on VBR. However, such differences between the two techniques reduce progressively as VBR is raised. The differences vanish for VBR ≥ 100 V, for which both techniques can improve the VBR by ≥ 2.5 times. Although focused primarily on breakdown, our work gives quick calculations showing that the high-k passivation has 5 – 10 % higher gate-drain capacitance than the gate-connected FP.

中文翻译：

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高 k 钝化和栅极连接场板技术在增强 GaN HEMT 击穿方面的相对有效性

摘要 先前的工作表明，AlGaN/GaN 高电子迁移率晶体管 (HEMT) 的关态击穿电压 VBR 可以通过将栅极的漏极端扩展为场板 (FP) 或高 k在 AlGaN 层上钝化。然而，这两种技术尚未进行比较，其有效性被证明的 VBR ≥120 V。高 k 钝化避免了实现 FP 所涉及的光刻，实际器件的 VBR 可以下降到几十个伏特。因此，目前的工作通过 TCAD 模拟比较了这些技术的有效性，并建立了以下内容。在几十伏特的 VBR 下，高 k 钝化的效果远不如 FP，例如对于 VBR = 28 V 的器件，0.7 μm 长的 FP 在 0.105 μm 厚的 SiN 上使 VBR 翻倍至 56 V，而即使一个 0。5 μm 厚的 HfO2 钝化 (er = 20) 对 VBR 几乎没有影响。但是，随着 VBR 的提高，这两种技术之间的这种差异会逐渐减小。VBR ≥ 100 V 时差异消失，这两种技术都可以将 VBR 提高 ≥ 2.5 倍。尽管主要关注击穿，但我们的工作给出了快速计算，表明高 k 钝化具有比栅极连接的 FP 高 5 – 10% 的栅漏电容。