金刚石散热片对GaN FET性能的静电影响
Electrostatic Influence of Diamond Heat-Spreaders on GaN FET Performance
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中文总结 AI 辅助
本研究通过Sentaurus TCAD和Silvaco TCAD建模发现，金刚石散热片可提升GaN FET的热性能，但会引发界面静电问题，提出引入工程化中间层的方案以缓解该问题。
中文摘要 AI 辅助
金刚石具有优异的热导率，被广泛研究用作散热片以改善基于GaN的功率电子和射频电子的热管理。本研究使用Sentaurus TCAD对集成金刚石散热片的AlGaN/GaN高电子迁移率晶体管（HEMT）进行建模，纳入热边界电阻（TBR）、随温度变化的带隙窄化等先进物理模型。尽管金刚石可显著增强散热，但模拟揭示了一个重要却常被忽视的权衡：金刚石与半导体界面处的静电调制。我们首先对全向集成金刚石的p-GaN HEMT进行建模，其结果与实验报道的金刚石散热片集成带来的电热效益一致；但同时观察到金刚石/GaN界面处存在强带弯曲，伴随电场产生及金刚石中价带能量升高，进而在GaN表面形成界面空穴积累区，改变垂直输运并阻碍电流注入，导致无法获得高开态电流。这些结果表明，金刚石虽可提升热性能，但也会主动影响晶体管的静电特性。为同时解决升高的TBR和不期望的界面带弯曲问题，我们提出引入工程化中间层的方案；基于Sentaurus TCAD的结果，我们开发了Silvaco TCAD的传输线模型（TLM）测试结构，以表征空穴积累区形成的程度，为后续通过中间层开发缓解该问题的研究提供参考。
英文摘要
Diamond, with its exceptional thermal conductivity, is widely explored as a heat spreader to improve thermal management in GaN-based power and RF electronics. In this work, we use Sentaurus TCAD to model AlGaN/GaN HEMTs with integrated diamond heat spreaders, incorporating advanced physical models such as thermal boundary resistance (TBR) and temperature-dependent bandgap narrowing. While diamond significantly enhances heat dissipation, our simulations reveal an important but often overlooked tradeoff: electrostatic modulation at the diamond and semiconductor interface. We initially modeled a p-GaN HEMT with all-around diamond integration and show agreement to the experimentally reported electrothermal benefits of diamond heat spreader integration. However, we observe strong band bending at the diamond/GaN interface alongside electric field generation and increased valence band energy in diamond. As a result, an interfacial hole accumulation region forms at the GaN surface, altering vertical transport and hindering current injection which prevents high on-state current. These results indicate that although diamond improves thermal performance, it can also actively influence the electrostatics of the transistor. To address both the elevated TBR and the undesired interfacial band bending, we propose the incorporation of an engineered interlayer. Building on our Sentaurus TCAD results, we develop a Silvaco TCAD TLM test structure to characterize the extent of the hole accumulation region formation and give insight to future studies on mitigation through interlayer development.
