(Ga,Fe)Sb is a promising magnetic semiconductor (MS) for spintronic applications because its Curie temperature (T_C) is above 300 K when the Fe concentration is higher than 20%. However, the anisotropy constant K_u of (Ga,Fe)Sb is below 7.6 × 10³ erg/cm³ when Fe concentration is lower than 30%, which is one order of magnitude lower than that of (Ga,Mn)As. To address this issue, we grew Ga_1-x-yFe_xNi_ySb films with almost the same x (≈24%) and different y to characterize their magnetic and electrical transport properties. We found that the magnetic anisotropy of Ga_0.76-yFe_0.24Ni_ySb can be enhanced by increasing y, in which K_u is negligible at y = 1.7% but increases to 3.8 × 10⁵ erg/cm³ at y = 6.1% (T_C = 354 K). In addition, the hole mobility (μ) of Ga_1-x-yFe_xNi_ySb reaches 31.3 cm²/(V?s) at x = 23.7%, y = 1.7% (T_C = 319 K), which is much higher than the mobility of Ga_1-xFe_xSb at x = 25.2% (μ = 6.2 cm²/(V?s)). Our results provide useful information for enhancing the magnetic anisotropy and hole mobility of (Ga,Fe)Sb by using Ni co-doping.

提出了一种改进的高电子迁移率晶体管寄生电阻提取方法，该方法利用了特殊偏置点（V_gs > V_th，V_ds = 0 V）的等效电路模型，推导了寄生电阻的表达式，采用半分析法对寄生电阻进行了优化。1 ~110 GHz S参数实测结果和仿真的S参数一致，证明该方法是有效的。

Indium-tin-zinc oxide (ITZO) thin-film transistor (TFT) technology holds promise for achieving high mobility and offers significant opportunities for commercialization. This paper provides a review of progress made in improving the mobility of ITZO TFTs. This paper begins by describing the development and current status of metal-oxide TFTs, and then goes on to explain the advantages of selecting ITZO as the TFT channel layer. The evaluation criteria for TFTs are subsequently introduced, and the reasons and significance of enhancing mobility are clarified. This paper then explores the development of high-mobility ITZO TFTs from five perspectives: active layer optimization, gate dielectric optimization, electrode optimization, interface optimization, and device structure optimization. Finally, a summary and outlook of the research field are presented.

A physics-based analytical expression that predicts the charge, electrical field and potential distributions along the gated region of the GaN HEMT channel has been developed. Unlike the gradual channel approximation (GCA), the proposed model considers the non-uniform variation of the concentration under the gated region as a function of terminal applied voltages. In addition, the model can capture the influence of mobility and channel temperature on the charge distribution trend. The comparison with the hydrodynamic (HD) numerical simulation showed a high agreement of the proposed model with numerical data for different bias conditions considering the self-heating and quantization of the electron concentration. The analytical nature of the model allows us to reduce the computational and time cost of the simulation. Also, it can be used as a core expression to develop a complete physics-based transistor Ⅳ model without GCA limitation.

In this work, the GaN p-MISFET with LPCVD-SiN_x is studied as a gate dielectric to improve device performance. By changing the Si/N stoichiometry of SiN_x, it is found that the channel hole mobility can be effectively enhanced with Si-rich SiN_x gate dielectric, which leads to a respectably improved drive current of GaN p-FET. The record high channel mobility of 19.4 cm²/(V?s) was achieved in the device featuring an Enhancement-mode channel. Benefiting from the significantly improved channel mobility, the fabricated E-mode GaN p-MISFET is capable of delivering a decent-high current of 1.6 mA/mm, while simultaneously featuring a negative threshold-voltage (V_TH) of –2.3 V (defining at a stringent criteria of 10 μA/mm). The device also exhibits a well pinch-off at 0 V with low leakage current of 1 nA/mm. This suggests that a decent E-mode operation of the fabricated p-FET is obtained. In addition, the V_TH shows excellent stability, while the threshold-voltage hysteresis ΔV_TH is as small as 0.1 V for a gate voltage swing up to –10 V, which is among the best results reported in the literature. The results indicate that optimizing the Si/N stoichiometry of LPCVD-SiN_x is a promising approach to improve the device performance of GaN p-MISFET.

本文采用金属有机化学气相沉积（MOCVD）生长原位SiNx栅介质制备了用于Ka波段高功率毫米波应用的AlN/GaN金属绝缘体半导体高电子迁移率晶体管（MIS-HEMTs）。原位生长SiN_x栅介质显著抑制了栅反向漏电、栅介质/AlN界面态密度和电流坍塌。所研制的MIS HEMTs在V_GS= 2 V时最大饱和输出电流为2.2 A/mm，峰值跨导为509 mS/mm，在V_GS = -30 V时肖特基栅漏电流为4.7×10^-6 A/mm。采用0.15 μmT形栅技术，获得98 GHz的f_T和165 GHz的f_MAX。大信号测量表明，在连续波模式下，漏极电压V_DS = 8 V时，MIS HEMT在40 GHz下输出功率密度2.3 W/mm，45.2%的功率附加效率（PAE），而当V_DS增加到15 V时，功率密度提升到5.2 W/mm，PAE为42.2%。