In this work, highly linear AlGaN/GaN laterally gated (or buried gate) high-electron-mobility transistors (HEMTs) are reported. The effect of gate dimensions on source-access resistance and the linearity of laterally gated devices are investigated experimentally in detail for the first time. Transistors with different gate dimensions and conventional planar devices are fabricated using two-step electron beam lithography (EBL). Current-voltage, source-access resistance, small-signal, and two-tone measurements are performed to evaluate the linearity of devices. Contrary to conventional planar HEMTs, the intrinsic transconductance of laterally gated devices monotonically increases with increasing gate voltage, showing a similar behavior as junction field-effect transistors (FETs). The source-access resistance shows a polynomial increase with the drain current, which can be reduced by decreasing the filling ratio of the buried gates. Through the optimization of these two competing factors, i.e., intrinsic transconductance and the source-access resistance, flat transconductance with high linearity is achieved experimentally. The laterally gated structure shows flat transconductance and small-signal power gain over a larger span of gate voltage that is 2.5 times higher than a planar device. Moreover, 6.9-dB improvement in output intercept point (OIP3)/PDC is achieved. This approach can be used to improve the linearity of AlGaN/GaN HEMTs at the device level.

中文翻译：

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具有优化线性度的 AlGaN/GaN 横向栅极高电子迁移率晶体管


在这项工作中，报道了高度线性的 AlGaN/GaN 横向栅极（或埋栅）高电子迁移率晶体管（HEMT）。首次通过实验详细研究了栅极尺寸对源极访问电阻和横向栅极器件线性度的影响。具有不同栅极尺寸的晶体管和传统平面器件是使用两步电子束光刻（EBL）制造的。执行电流电压、源接入电阻、小信号和双音测量来评估器件的线性度。与传统平面 HEMT 相反，横向栅极器件的固有跨导随着栅极电压的增加而单调增加，表现出与结型场效应晶体管 (FET) 类似的行为。源极-存取电阻随漏极电流呈多项式增加，可以通过降低掩埋栅的填充率来降低源极-存取电阻。通过对本征跨导和源极接入电阻这两个竞争因素的优化，在实验上实现了具有高线性度的平坦跨导。横向栅极结构在更大的栅极电压跨度上表现出平坦的跨导和小信号功率增益，比平面器件高 2.5 倍。此外，输出截取点 (OIP3)/PDC 提高了 6.9 dB。这种方法可用于提高 AlGaN/GaN HEMT 在器件层面的线性度。