A discrete GaN power transistor’s substrate is typically connected to its source electrode. However, on the GaN-on-Si power IC platform, the high-side transistor (HS-transistor) and low-side transistor (LS-transistor) share a common substrate that cannot be simultaneously connected to both source electrodes of the two transistors. Thus, the termination of the common substrate remains an undecided issue. In this work, comprehensive TCAD simulations are exploited to reveal the influences of various substrate termination schemes. It is found the common substrate inevitably leads to severe degradation in the dynamic ${R} _{\mathrm{ ON}}$ due to back-gating effects. The mechanisms for the degradations vary with the substrate termination scheme, and will be discussed in detail. To address these issues, we propose a new GaN power IC platform on an engineered bulk silicon substrate, and study the new platform with TCAD simulations. The proposed platform provides a local electrical substrate (a p+ island) for each GaN power transistor. The source electrode of each GaN transistor is connected to its local electrical substrate, while all devices share a common mechanical substrate. The junctions between the local substrates and the underlying n-layer provide an effective isolation between GaN transistors. The back-gating effects are completely suppressed for the GaN integrated bridge circuit.

中文翻译：

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体硅衬底上的GaN集成桥电路：问题和建议的解决方案

分立GaN​​功率晶体管的衬底通常连接到其源电极。但是，在GaN-on-Si功率IC平台上，高端晶体管（HS晶体管）和低端晶体管（LS晶体管）共享一个公共基板，该基板无法同时连接到两个晶体管的两个源电极。因此，共用基板的终止仍然是未决的问题。在这项工作中，利用全面的TCAD仿真来揭示各种基板端接方案的影响。发现常见的基材不可避免地导致动态性能的严重降低。 $ {R} _ {\ mathrm {ON}} $ 由于背门效应。降解的机制随基板终止方案而变化，将进行详细讨论。为了解决这些问题，我们在工程大块硅衬底上提出了一个新的GaN功率IC平台，并通过TCAD仿真研究了该新平台。所提出的平台为每个GaN功率晶体管提供了一个局部电衬底（一个p +岛）。每个GaN晶体管的源电极都连接到其本地电气基板，而所有设备都共享一个公共的机械基板。局部衬底和下面的n层之间的结提供了GaN晶体管之间的有效隔离。GaN集成桥电路的背栅效应被完全抑制。