We investigated the impact of a sulfur passivation (S-passivation) process step on carrier transport properties of surface-channel In _0.7 Ga _0.3 As quantum-well (QW) Metal-Oxide-Semiconductor Field-Effect-Transistors (MOSFETs) with source/drain (S/D) regrowth contacts. To do so, we fabricated long-channel In _0.7 Ga _0.3 As QW MOSFETs with and without (NH ₄ ) ₂ S treatment prior to a deposition of Al ₂ O ₃ /HfO ₂ = 1-nm/3-nm by atomic-layer-deposition (ALD). The devices with S-passivation exhibited a lower value of subthreshold-swing (S) = 74 mV/decade and more positive shift in the threshold voltage ( $\text{V}_{\mathrm{ T}}$ ) than those without S-passivation. From the perspective of carrier transport, S-passivated devices displayed excellent effective mobility ( $\mu _{eff}$ ) in excess of 6,300 cm ² / $\text{V}\cdot \text{s}$ at 300 K. It turned out that the improvement of $\mu _{eff}$ was attributed to reduced Coulombic and surface-roughness scatterings. Using a conductance method, a fairly small value of interface trap density $({\mathrm{ D}}_{\mathrm{ it}}) = 1.56 \times 10^{12}$ cm $^{-2}$ eV $^{-1}$ was obtained for the devices with S-passivation, which was effective in mitigating the Coulombic scattering at the interface between the high-k dielectric layer and the In _0.7 Ga _0.3 As surface-channel layer.

中文翻译：

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硫钝化对In _0.7 Ga _0.3 As量子阱MOSFET载流子输运性能的影响

我们研究了硫钝化（S-钝化）工艺步骤对表面沟道In _0.7 Ga _0.3 As量子阱（QW）金属氧化物半导体场效应晶体管（MOSFET）具有源极/漏极（S / D）再生触点。为此，我们在通过原子层 沉积Al ₂ O ₃ / HfO ₂ = 1-nm / 3-nm之前，制造了 具有和不具有（NH ₄ ） ₂ S处理的 长沟道In _0.7 Ga _0.3 As QW MOSFET。 沉积（ALD）。具有S钝化的器件的亚阈值摆幅（S）= 74 mV / decade的值较低，并且阈值电压（ $ \ text {V} _ {\ mathrm {T}} $ ）比没有S钝化的那些。从载流子传输的角度来看，S钝化设备显示出出色的有效移动性（ $ \ mu _ {eff} $ ）超过6,300 cm ² / $ \ text {V} \ cdot \ text {s} $ 在300K。事实证明， $ \ mu _ {eff} $ 归因于减少了库仑散射和表面粗糙度散射。使用电导方法，界面陷阱密度的值相当小 $（{\ mathrm {D}} _ {\ mathrm {it}}）= 1.56 \ times 10 ^ {12} $ 厘米 $ ^ {-2} $ 电子伏特 $ ^ {-1} $ 对于具有S钝化的器件，获得了有效的材料，它可以有效地缓解高k介电层和In _0.7 Ga _0.3 As表面沟道层之间界面的库仑散射 。