绝缘层上半导体多晶膜激光再结晶临界条件

从理论的角度分析了绝缘衬底对其上面半导体多晶膜激光熔化再结晶过程的影响, 发现低导热的绝缘层使产生固一液相变的临界激光功率有明显的降低.用喇曼光谱测量了激光再结晶SOI层中的应力. 应力的出现是多晶膜内曾经发生过固一液相的佐证.从这一思想出发, 对LPCVD方法制备的大量SOI 样品进行激光再结晶临界条件的研究, 证明了忽略绝缘层低热导影响的模型不能解释实验结果, 而经过修正的公式则可以较好地拟合实验结果, 关键词：     

溶胶-凝胶VO2薄膜转换特性研究

利用溶胶凝胶法在SiO2Si衬底上沉积高取向的V2O5薄膜,在压强低于2Pa,温度高于400℃的条件下,对V2O5薄膜进行真空烘烤,获得了电阻率变化3个数量级以上、弛豫宽度为62℃的VO2多晶薄膜.以X射线衍射(XRD)、扫描电子显微镜(SEM)图和电阻率转换特性等实验结果为依据,详细分析了溶胶凝胶薄膜在真空烘烤时从V2O5向VO2的转化,它经历了从VnO2n+1(n=2,3,4,6)到VO2的过程.实验证明,根据选择合适的成膜热处理条件和真空烘烤条件是实现溶胶凝胶V2O5结构向VO2结构成功转换的关键 关键词： 溶胶-凝胶法 氧化钒薄膜 VO2膜转换特性     

P2+和P+注入硅固相外延过程时间分辨的反射率研究

本文以时间分辨的反射率测量结合背散射和沟道分析、透射电子显微镜分析,比较和研究了在77K温度下180keV,1×10¹⁴/cm²P₂⁺和90KeV,2×10¹⁴/cm²P⁺注入硅于550℃退火时的固相外延过程。发现了P₂⁺,P⁺注入硅样品的固相外延过程具有不同的特征。这种差异是由于P₂⁺和P⁺在硅中引入不同的损伤造成的。P⁺注入的硅样品测量得到的时间分辨的反射谱是反常的。这种反常谱可用样品退火时从表面层到非晶硅层与从衬底到非晶硅层的双向外延的过程给出满意的解释。 关键词：     

SOI新结构——SOI研究的新方向

SOI（silicon-on-insulator：绝缘体上单晶硅薄膜）技术已取得了突破性的进展，但一般SOI结构是以SiO2作为绝缘埋层，以硅作为顶层的半导体材料，这样导致了一些不利的影响，限制了其应用范围。为解决这些问题和满足一些特殊器件／电路的要求，探索研究新的SOI结构成为SOI研究领域新的热点。如SOIM，GPSOI，GeSiOI，SionAlN，SiCOI，GeSiOI，SSOI等。文章将结合作者的部分工作，报道SOI新结构研究的新动向及其应用。     

一种新型的光纤锥形耦合器

提出了一种光纤波导折射率渐变的新型锥形（Taper）耦合器件，其原理是基于光纤中Ge缺陷在紫外光照射下而产生的光致折射率的变化。利用光纤在高压、低温下渗氢技术使单模光纤的光致折射率变化△n达6×10-3数量级；通过控制曝光条件就可以在光纤中产生一定规律的锥形结构，使单模光纤的模场半径由4．8μm缩小到3．2μm。由耦合波理论分析表明该器件具有较好的基模传输特性。     

FORMATION OF A BURIED LAYER OF ALUMINIUM NITRIDE BY HIGH DOSE N2+ IMPLANTATION INTO ALUMINIUM

Aluminium films with various thickness between 700 nm and 1μm were deposited on Si (100) substrates, and 400 keV N₂⁺ ions with doses ranging from 4.3×10¹⁷ to 1.8×10¹⁸ N/cm² were implanted into the alu-minium films on silicon, Rutherford Backscattering (RBS) and channeling, secondary ion mass spectroscopy (SIMS), Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and spreading resistance probes (SRP) were used to characterize the synthesized aluminium nitride. The experiments showed that when the implantation dose was higher than a critical dose N_c, a buried stoichiometric AlN layer with high resistance was formed, while no apparent AlN XRD peaks in the as-implanted samples were observed; however, there was a strong AlN(100) diffraction peak appearing after annealing at 500 ℃ for 1h. The computer program, Implantation of Reactive Ions into Silicon (IRIS), has been modified and used to simulate the formation of the buried AlN layer as N₂⁺ is implanted into aluminium. We find a good agreement between experimental measurements and IRIS simulation.     

PULSED LASER DEPOSITION AND CHARACTERIZATION OF FERHOELECTHIC Pb(Zr, Ti)O3 THIN FILMS ON SILICON-ON-INSULATOR SUBSTRATES

Ferroelectric Pb(Zr, Ti)O₃ thin films were prepared by pulsed exeimer laser deposition on silicon-on-insulator and Pt-coated silicon-on-insulator substrates, and rapid thermal annealing was per-formed to crystallize the films, Based on the analysis by X-ray diffraction, Rutherford backscattering spectroscopy and measurements of electrical properties, the films were revealed to be polycrystalline perovskite structure with mainly (100) and (110) orientations, and their crystallization was found to be dependent on annealing temperature and annealing time. The films show good ferroelectricity, with P_r=15μC/cm², E_c= 50kV/cm, high resistivity and high dielectric constant.     

半导体的CO2激光退火和合金化

本文主要研究连续CO₂激光对半导体的照射效应。实验结果与理论分析说明,用连续CO₂激光照射可将半导体样片加热到所需的温度。与其它短波长的激光不同,波长为10.6μm的连续CO₂激光照射半导体有如下特点:CO₂激光是借助于自由载流子吸收与半导体耦合;样片在深度方向被均匀加热;激光背面照射可以增强退火效果。连续CO₂激光照射可以固相外延再生长的方式使As离子注入Si的损伤层退火恢复。在再生长的过程中注入的As离子进入替位,电激活率很高,而且不发生杂质再分布。将连续CO₂激光背面照射成功地应用于GaAsFET制备欧姆接触,既可避免激光正面照射对器件结构的破坏,又能得到比热退火为好的电学性能。 关键词：     

Improvement of total-dose irradiation hardness of silicon-on-insulator materials by modifying the buried oxide layer with ion implantation

The hardening of the buried oxide (BOX) layer of separation by implanted oxygen (SIMOX) silicon-on-insulator (SOI) wafers against total-dose irradiation was investigated by implanting ions into the BOX layers. The tolerance to total-dose irradiation of the BOX layers was characterized by the comparison of the transfer characteristics of SOI NMOS transistors before and after irradiation to a total dose of 2.7 Mrad(SiO₂. The experimental results show that the implantation of silicon ions into the BOX layer can improve the tolerance of the BOX layers to total-dose irradiation. The investigation of the mechanism of the improvement suggests that the deep electron traps introduced by silicon implantation play an important role in the remarkable improvement in radiation hardness of SIMOX SOI wafers.     

PULSED LASER DEPOSITION AND CHARACTERIZATION OF FERHOELECTHIC Pb(Zr,Ti)O3 THIN FILMS ON SILICON-ON-INSULATOR SUBSTRATES

Ferroelectric Pb(Zr, Ti)O₃ thin films were prepared by pulsed exeimer laser deposition on silicon-on-insulator and Pt-coated silicon-on-insulator substrates, and rapid thermal annealing was per-formed to crystallize the films, Based on the analysis by X-ray diffraction, Rutherford backscattering spectroscopy and measurements of electrical properties, the films were revealed to be polycrystalline perovskite structure with mainly (100) and (110) orientations, and their crystallization was found to be dependent on annealing temperature and annealing time. The films show good ferroelectricity, with P_r=15μC/cm², E_c= 50kV/cm, high resistivity and high dielectric constant.