用瞬态激励分析法模拟半导体器件的交流特性

基于傅里叶变换的瞬态激励法是一种模拟半导体器件交流特性的计算技术。本文详细介绍了这种方法的原理和具体使用方法，并且给出了用这种方法模拟Ｓｉ－ＳｉＧｅ－Ｓｉ异质结双极晶体管的结果。     

Hydrophilicity of anatase TiO2/Cr-doped TiO2 thin films with different band gaps

Based on the concept that the electron-hole separation effect caused by a different band-gap structure would improve its hydrophilicity, anatase-TiO₂/Cr-doped TiO₂ thin films were synthesized by DC magnetron sputtering. The optical band gaps of TiO₂ thin films decreased from 3.23 to 2.95 eV with increasing Cr-doping content. Multilayer TiO₂ thin films with different band gaps exhibited a superhydrophilicity under UV illumination. In particular, in anatase TiO₂ (3.23 eV)/4.8% Cr-doped TiO₂ (2.95 eV), the hydrophilicity, which indicated a contact angle of less than 20°, lasted for 48 h in the dark after UV illumination was discontinued. This outstanding result has rarely been reported for TiO₂ thin films, which confirmed that the prominent superhydrophilicity of anatase TiO₂/Cr-doped TiO₂/glass could be attributed to the retardation of electron-hole recombination caused by the band-gap difference.     

国内MOCVD化合物半导体材料的新进展

金属有机气相沉积法(MOCVD)已受到国内外普遍重视,MOCVD技术所用的关键原材料也已研制成功。近年来,国内采用MOCVD技术在GaAs衬底上已生长出GaAlAs、HgCdTe、ZnSe等异质结材料,以InP、CaF_2作衬底,也生长了某些半导体薄膜材料。     

Properties of nitrogen diluted hydrogenated amorphous carbon (n-type a-C:H) films and their realization in n-type a-C:H/p-type crystalline silicon heterojunction diodes

Nitrogen incorporated hydrogenated amorphous carbon (a-C:N:H) films were grown in an asymmetric rf PECVD system using C₂H₂ and N₂ gaseous mixture. Deposition rate, stress, hardness, optical bandgap, refractive index, and electrical characteristics have been studied as a function of self bias. Microstructures of these films were also studied using LASER Raman technique. Finally nitrogen diluted a-C:H films were realized as n-type semiconductor in n-type a-C:H/p-type crystalline silicon hetrojunction diodes. Current-voltage (I-V) and capacitance-voltage (C-V) characteristics have also been studied as a function of self bias on these heterojunction diodes.