An enhancement-mode hydrogen-terminated diamond field-effect transistor (FET) is realized by using a low work function gate material, namely, lanthanum hexaboride (LaB₆). The reason for the enhancement mode should be that the electrons in the LaB₆ layer flow into the two-dimensional hole gas (2DHG) channel and compensate the holes, such that the channel is shut down. The threshold voltages ( ${\mathrm {V}}_{\text {TH}}$ ) range from − 0.29 V to − 0.72 V with different gate lengths. The device with 2 $\mu \text{m}$ gate length shows a − 57.9 mA/mm maximum drain current density ( ${\mathrm {I}}_{\text {DSmax}}$ ) at ${\mathrm {V}}_{\text {GS}} =-$ 5 V. The on/off ratio is around 9 orders of magnitude, with a subthreshold swing of 130 mV. Effective mobility ( $\mu _{\text {eff}}$ ) as high as 195.4 cm²/ $\text{V}\cdot \text{s}$ is obtained from the device. This technique reveals undamaged 2 DHG characteristics, uncontaminated interface between LaB₆ and aluminum gate metal, and a simple fabrication process, which will promote the development of enhancement diamond FETs.

中文翻译：

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六硼化镧栅极材料的增强型氢端接金刚石场效应晶体管

通过使用低功函数栅极材料，即六硼化镧（LaB ₆），实现了增强型氢端接金刚石场效应晶体管（FET ）。增强模式的原因应该是LaB ₆层中的电子流入二维空穴气体（2DHG）通道并补偿空穴，从而使通道关闭。阈值电压（ ${\mathrm {V}}_{\text {TH}}$ ) 范围从 − 0.29 V 到 − 0.72 V，具有不同的栅极长度。该设备具有 2 $\mu \text{m}$ 栅极长度显示 − 57.9 mA/mm 最大漏极电流密度 ( ${\mathrm {I}}_{\text {DSmax}}$ ） 在 ${\mathrm {V}}_{\text {GS}} =-$ 5 V。开/关比约为 9 个数量级，亚阈值摆幅为 130 mV。有效流动性（ $\mu _{\text {eff}}$ ) 高达 195.4 cm ² / $\text{V}\cdot \text{s}$ 是从设备中获取的。该技术揭示了未损坏的 2 DHG 特性、未受污染的 LaB ₆和铝栅极金属之间的界面以及简单的制造工艺，这将促进增强型金刚石 FET 的发展。