功率晶体管芯片的电泳法玻璃钝化研究

本文介绍了电泳法淀积7801—5锌系玻璃粉钝化功率晶体管芯,并对电泳法原理、影响因素、玻璃粉烧结工艺进行了探讨;对钝化前后的器件做了测试;管芯反向漏电流得到改善,钝化后管芯分别在250℃和175℃温度下进行高温贮存试验取得满意结果.说明电泳法淀积7801—5锌系玻璃粉钝化工艺可提高半导体器件的稳定性和可靠性.     

Chemical and electrical stabilities of organic thin‐film transistors for display application

Abstract— The chemical and electrical stabilities of pentacene organic thin‐film transistors (OTFTs) fabricated on plastic by a self‐organized process was studied. The degradation in on‐current, threshold voltage, and field‐effect mobility of the OTFT under air exposure can be expressed in exponential form in time and can be reduced by using multilayer passivation on the organic semiconductor, which reduces the penetration of H₂O and O₂ into the pentacene. The threshold voltage degrades during negative gate bias stress, which can be reduced significantly by optimizing the organic gate insulator used for the OTFT. A stable OTFT can be fabricated by using the proper organic gate insulator.     

压铸镁合金AZ91表面化学镀Ni P合金研究

研究了压铸镁合金AZ91的表面化学镀镍磷合金的工艺，利用X射线衍射(XRD)、扫描电镜SEM)、能谱(XPS)及极化曲线的测量等方法，探讨了镁合金表面化学镀Ni P层的组织、相、成分及其耐蚀性，结果显示，镁合金化学镀Ni-P合金镀层在350 ℃热处理后成晶态，镀层成分为NiP、Ni₂P等.化学镀Ni-P合金镀层在3.5% NaCl中的极化曲线存在明显的钝化区，且钝化区呈直线均匀，耐蚀性较好.     

过氧化氢钝化工艺的改进

传统的过氧化氢钝化工艺较难掌握，钝化条件比较苛刻，钝化效果一般，还容易出现一种褐色不明附着物。经过大量试验研究，对过氧化氢钝化工艺进行了改进，钝化效果明显提高。     

Advances in pulsed-laser-deposited AIN thin films for high-temperature capping, device passivation, and piezoelectric-based RF MEMS/NEMS resonator applications

In this paper we report recent advances in pulsed-laser-deposited AIN thin films for high-temperature capping of SiC, passivation of SiC-based devices, and fabrication of a piezoelectric MEMS/NEMS resonator on Pt-metallized SiO₂/Si. The AlN films grown using the reactive laser ablation technique were found to be highly stoichiometric, dense with an optical band gap of 6.2 eV, and with a surface smoothness of less than 1 nm. A low-temperature buffer-layer approach was used to reduce the lattice and thermal mismatch strains. The dependence of the quality of AlN thin films and its characteristics as a function of processing parameters are discussed. Due to high crystallinity, near-perfect stoichiometry, and high packing density, pulsed-laser-deposited AlN thin films show a tendency to withstand high temperatures up to 1600°C, and which enables it to be used as an anneal capping layer for SiC wafers for removing ion-implantation damage and dopant activation. The laser-deposited AlN thin films show conformal coverage on SiC-based devices and exhibit an electrical break-down strength of 1.66 MV/cm up to 350°C when used as an insulator in Ni/AlN/SiC metal-insulator-semiconductor (MIS) devices. Pulsed laser deposition (PLD) AlN films grown on Pt/SiO₂/Si (100) substrates for radio-frequency microelectrical and mechanical systems and nanoelectrical and mechanical systems (MEMS and NEMS) demonstrated resonators having high Q values ranging from 8,000 to 17,000 in the frequency range of 2.5–0.45 MHz. AlN thin films were characterized by x-ray diffraction, Rutherford backscattering spectrometry (in normal and oxygen resonance mode), atomic force microscopy, ultraviolet (UV)-visible spectroscopy, and scanning electron microscopy. Applications exploiting characteristics of high bandgap, high bond strength, excellent piezoelectric characteristics, extremely high chemical inertness, high electrical resistivity, high breakdown strength, and high thermal stability of the pulsed-laser-deposited thin films have been discussed in the context of emerging developments of SiC power devices, for high-temperature electronics, and for radio frequency (RF) MEMS.     

Study on Surface Treatments on CdSe Wafers

The surface treatments on CdSe wafers were studied by means of SEM, XPS and micro-current test instrument. The relations between electrical properties of CdSe wafers and surface topography, composition and structure were analyzed. The results show that the change of surface composition by etching is beneficial to decrease leakage current. Meanwhile, the increase of oxygen on surface caused by passivation can largely decrease leakage current. When passivating time is 40 min, the wafers surface appears smooth and compact, which will decrease the density of surface state, the optimal electrical property of the wafer is therefore obtained.     

合金元素对铸造奥氏体不锈钢组织及耐蚀性能的影响

研究了Cr、Mo等合金元素对铸造奥氏体不锈钢析出相的成份、结构及形貌的影响。测定七种铸造奥氏体不锈钢在20％H_2SO_4及含有不同Cl~-浓度的20％H_2SO_4中的均匀腐蚀速度、稳定电位和极化曲线。实验结果表明:合金元素Cr、Mo促进了针状σ相析出;合金元素Cr、Mo、Cu不同程度地提高了钢的抗均匀腐蚀性能和抗点蚀性能。     

Opportunities in silicon photovoltaics and defect control in photovoltaic materials

Silicon is the dominant semiconductor material in use for terrestrial photovoltaic cells. The critical issues in cell design, materials specification and cell processing are reviewed. Specific attention is given to light trapping, minority carrier lifetime control and novel microstructures for enhancing photon absorption. Relevant topics in generic defect control are discussed with particular emphasis on compound semiconductor materials.     

钝化膜提高GaN基LED光提取效率研究

模拟计算了光的入射角度与反射率的关系,当光的入射角度大于23°时,发生全反射,无论是否在器件表面生长增透膜,这时的光都无法从器件顶部出射表面提取出来。研究了使用等离子体增强化学气相沉积法(PECVD)在已经制备了n电极和p电极的GaN基LED上制备钝化膜,分析了SiON和SiN_x膜沉积对于器件的光输出功率的影响。通过实验证明,在器件上沉积SiON后,光输出功率增加。     

Passivation of Surface and Interface States in AlGaN/GaN HEMT Structures by Annealing

The Ni/AlGaN interfaces in AlGaN/GaN Schottky diodes were investigated to explore the physical origin of post-annealing effects using electron beam induced current (EBIC), current–voltage (I–V) characteristics, and X-ray photoelectron spectroscopy (XPS). The EBIC images of the annealed diodes showed that the post-annealing process reduces electrically active states at the Schottky metal/AlGaN interfaces, leading to improvement of diode performance, for example a decrease in reverse leakage current and an increase in Schottky barrier heights. Pulsed I–V characteristics indicate the Fermi level is up-shifted after annealing, resulting in a larger sheet carrier density at the AlGaN/GaN interface. Unintentional oxidation of the free AlGaN surface during the post-annealing process, revealed by XPS analysis, may prevent electron trapping near the drain-side of the gate edges. We suggest that the post-annealing process under an optimized conditions can be an effective way of passivating AlGaN/GaN heterojunction field-effect transistors.