AlGaN基PIN光电探测器的模型与模拟

在漂移扩散方程的基础上建立了AlGaN p-I-n光电探测器的物理模型,分析了多种结构AlGaN p-I-n光电探测器的光谱响应,并讨论了AlGaN/GaN异质结界面极化效应对太阳盲区p-GaN/I-Al0.33Ga0.67N/n-GaN倒置异质结结构p-I-n光电探测器(inverted heterostructure photodetectors,IHPs)UV/Solar选择比(280nm与320nm响应度之比)的影响．结果表明：优化p层是提高器件光谱响应的有效途径;为获得较高的UV/Solar选择比,光伏模式(零偏压)为太阳盲区p-GaN/I-Al0.33Ga0.67N/n-GaN IHPs的最佳工作模式;在光伏模式下考虑极化效应影响时,Ga面p-GaN/I-Al0.33Ga0.67N/n-GaN IHPs器件的UV/Solar选择比可达750,与Tarsa等人报道的三个量级的实验结果基本一致．     

C波段限幅开关集成芯片

采用GaAs p-i-n二极管单片集成工艺技术研制出C波段限幅开关集成芯片,该芯片集成了微波限幅器和单刀单掷(SPST)开关功能,尺寸仅为2.5 mm×1.0 mm。采用偏置相关S参数测试法建立可定标的p-i-n二极管器件模型,精准的器件模型保证集成芯片一次流片成功。实测结果显示,该芯片在5～6 GHz频率范围内插入损耗小于1 dB,隔离度大于50 dB,电压驻波比小于1.5∶1,开关速度小于25 ns,可承受10 W以上的连续波功率。该集成芯片在T/R组件接收通道可替代两只单一功能芯片,有较好的应用前景。     

An initial investigation of amorphous silicon-selenium solar cells

Amorphous silicon-selenium solar cells, where a selenium alloy thin film was used as an intrinsic layer, were successfully fabricated by plasma-enhanced chemical vapor deposition. The cells have a simple p-i-n structure. The maximum conversion efficiency of the cells was 5.1 %, measured under 100 mW/cm [2] ELH white light illumination. The fabricated selenium alloy solar cells exhibited stable characteristics under white light soaking, with respect to those of amorphous silicon comparison solar cells, fabricated under similar conditions. Measurement of the quantum efficiency showed that this cell can be used as a top cell in a tandem cell structure.     

Study of SiO2 encapsulation for aluminum and phosphorus implant activation in 4H-SiC

SiO₂ encapsulation layer was studied for aluminum (Al) and phosphorus (P) implant activation anneal in 4H-SiC. Both Al^- and P⁺ implantation were carried out at 650 °C followed by activation anneal at 1400 °C to 1500 °C. X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and four-point-probe (FPP) measurements were performed to examine surface stoichiometry, roughness, and sheet resistance of the implanted SiC regions. The effect of using SiO₂ encapsulation layer for Al implant activation on the performance of 4H-SiC p-i-n diodes with both p-type active region and JTE region formed by Al implantation was also investigated. Forward and reverse characteristics including saturation current density J₀, ideality factor η, reverser leakage current density J_L and threshold breakdown voltage V_BR have been extracted. The results show that SiO₂ encapsulation effectively protects the SiC surface during high temperature implant activation for both Al^- and P⁺.