Diamond electronic devices have attracted significant interest owing to their excellent semiconducting properties. We recently demonstrated that eliminating surface-transfer doping enhances carrier mobility and achieves normally off behavior in diamond field-effect transistors (FETs) with a hexagonal boron nitride (h-BN) gate insulator. In our previous study, the gate electrode was overlapped onto the source/drain electrodes to prevent the increase in access resistance caused by excluding surface-transfer doping. However, it is known that gate overlap increases parasitic capacitance and gate leakage current. In this study, we developed a technique for self-aligning the gate electrode with the edge of h-BN using oblique-angle deposition. The diamond FET with a self-aligned gate electrode exhibits optimal FET characteristics, including high mobility of ≈ 400 cm2V−1s−1, low sheet resistance of 2.4 kΩ, and output characteristics demonstrating pinch-off behavior. Furthermore, the capacitance-voltage characteristics clearly indicate distinct ON and OFF states, validating the efficacy of this technique. This method enables the fabrication of diamond/h-BN FETs with no gate overlap and without increasing access resistance, making it a promising approach for developing high-speed, low-loss diamond FETs with a wide range of applications.

中文翻译：

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用于氢封端金刚石场效应晶体管的自对准栅电极，带有六方氮化硼栅极绝缘体


金刚石电子器件因其优异的半导体特性而引起了人们的极大兴趣。我们最近证明，消除表面转移掺杂可以提高载流子迁移率，并在具有六方氮化硼 （h-BN） 栅极绝缘体的金刚石场效应晶体管 （FET） 中实现常关行为。在我们之前的研究中，栅极重叠在源极/漏极电极上，以防止因排除表面转移掺杂而导致访问电阻增加。然而，众所周知，栅极重叠会增加寄生电容和栅极漏电流。在这项研究中，我们开发了一种使用斜角沉积将栅电极与 h-BN 边缘自动对准的技术。具有自对准栅极的金刚石 FET 表现出最佳的 FET 特性，包括 ≈ 400 cm2V-1s-1 的高迁移率、2.4 kΩ 的低薄层电阻以及表现出夹断行为的输出特性。此外，静电容量-电压特性清楚地表明了不同的 ON 和 OFF 状态，验证了该技术的有效性。这种方法能够制造出没有栅极重叠且不增加访问电阻的金刚石/h-BN FET，使其成为开发具有广泛应用的高速、低损耗金刚石 FET 的一种有前途的方法。