高质量栅氧化层的制备及其辐照特性研究

通过大量工艺实验开发了采用低温Ｈ２－Ｏ２合成氧化方法制备薄栅氧化层的工艺技术,得到了性能优良的薄栅氧化层,对于厚度为３０ｎｍ的栅氧化层,其平均击穿电压为３０Ｖ,Ｓｉ／ＳｉＯ２界面态密度小于３．５×１０１０ｃｍ－２．该工艺现已成功地应用于薄膜全耗尽ＣＭＯＳ／ＳＯＩ工艺中．同时还开展了采用低温Ｈ２－Ｏ２薄栅氧化工艺制备的全耗尽ＣＭＯＳ／ＳＯＩ器件的抗总剂量辐照特性研究,采用低温Ｈ２－Ｏ２合成氧化方法制备的ＳＯＩ器件的抗辐照特性明显优于采用常规干氧氧化方法制备的器件,Ｈ２－Ｏ２低温氧化工艺是制备抗核加固ＣＭＯＳ     

高度取向ZnO薄膜的介电和光波导特性研究

用溶胶凝胶法在不同的基片上制备了具有高度 ｃ 轴即（００２）取向的 Ｚｎ Ｏ 薄膜,研究了溶剂、稳定剂等对合成的先体溶液的影响。对薄膜的 Ｘ Ｒ Ｄ 分析表明随热处理温度的增加,ｃ 轴取向度增大,并且薄膜的晶粒尺寸在 ３００ ° Ｃ～５００ ° Ｃ 范围内增幅较大。用端面耦合的方法测量了制备在 Ｓｉ Ｏ２／ Ｓｉ（１１１）基片上薄膜的波导损耗,即随热处理温度的增加,波导损耗增大,主要来源于 Ｚｎ Ｏ 薄膜与 Ｓｉ Ｏ２ 的界面及晶粒的散射。制备在 Ｐｔ／ Ｓｉ Ｏ２／ Ｓｉ（１１１）基片上薄膜的相对介电常数为 ７～１３,电阻率则为 １．７×１０４ Ω·ｃｍ ～９．８×１０５ Ω·ｃｍ 。     

制造SiO2光波导的新工艺：紫外写入法

本文介绍国外利用ＧｅＯ２掺杂的ＳｉＯ２材料的紫外光敏性制造ＳｉＯ２光波导的研究情况，详细叙述了紫外写入法制造ＳｉＯ２光波导的工艺过程并概述了这种新的工艺优越性。     

担载Na,W,Mn的（001）SiO2单晶模型催化剂的SEM研究

用浸渍法制备了担载多组分Ｎａ、Ｗ、Ｍｎ的（００１）ＳｉＯ２单晶模型催化剂,并进行了ＸＰＳ和ＳＥＭ表征。研究结果表明,Ｎａ、Ｗ、Ｍｎ的多元组合使ＳｉＯ２转变为ｓｉＯ３＾２－能力的大小顺序依次为Ｗ－Ｍｎ〉Ｎａ－Ｗ－Ｍｎ〉Ｎａ－Ｍｎ〉Ｎａ－Ｗ,它们在ＳｉＯ２表面的形态各不相同,并且在ＳｉＯ２基体中的扩散程度比单组分强,表明它们之间可能在存着某种相互促进向ＳｉＯ基体中扩散的协同效应。     

多孔SiO_2厚膜湿度传感器的制造及其湿敏特性

用Ｓｏｌ－Ｇｅｌ方法制备了三种ＳｉＯ２凝胶，并以此制造了多孔ＳｉＯ２厚膜湿度传感器。其电容量－湿度关系呈开关特性，转变点约在８５％ＲＨ。     

Au掺杂TiO2／SiO2薄膜的光学非线性特性研究

采用溶胶－凝胶方法制备了Ａｕ掺杂的ＴｉＯ２／ＳｉＯ２复合薄膜（厚度约为１．０μｍ）。Ｘ－ｒａｙ衍射分析表明，Ａｕ的颗粒镶嵌在ＴｉＯ２／ＳｉＯ２复合薄膜的玻璃网络中。谢乐公式计算给出Ａｕ的颗粒大小约为１０ｎｍ。采用Ｚ－Ｓｃａｎ测量技术得此薄膜的光学非线性折射率为１．０９×１０－７ｅｓｕ。     

SiO2—Al2O3复合氧化物薄膜的溶胶—凝胶法制备研究

以ＴＥＯＳ和水合硝酸铝为原料用溶胶－凝胶法制备复合溶胶，对制备条件进行了研究，并用上述溶胶在不锈钢基体上制备了ＳｉＯ２－Ａｌ２Ｏ３复合氧化物薄膜。结果表明，该薄膜在适当组成时具有良好的完整性。当硝酸铝含量过高时溶胶和凝胶的均匀性受到影响。     

SO4^2—掺杂对YFeO3电导和气敏性能的影响

用浸泡震荡分散法制备了ＹＦｅＯ３掺ＳＯ４＾２－半导体气敏材料,并对其电志和气敏性能进行了研究。结果表明：ＳＯ４＾２－的掺入改变了ｐ型ＹＦｅＯ３,半遐体材料的导电性能;少量ＳＯ４＾２－（≈１％）的存在,能提高材料的比表面积和表面吸附氧Ｏ２＾ｎ－数量,２５７℃下对乙醇有较好的选择性和灵敏度。有望开发为一类新型酒敏元件。     

气敏器件用SnO_2薄膜材料

采用溶胶－凝胶法以ＳｎＣｌ２·Ｈ２Ｏ和ＺｒＯＣｌ２·８Ｈ２Ｏ为原料,制备出性能优良的纳米ＳｎＯ２薄膜材料。用Ｘ射线衍射仪分析了晶相,ＴＥＭ分析了微观结构。研究了掺杂、处理温度等对其性能的影响。在此基础上制作了ＳｎＯ２薄膜气敏器件,并检测了其气敏特性。     

WSi_2栅和Si栅CMOS／BESOI的高温特性分析

用厚膜ＢＥＳＯＩ（ＢｏｎｄｉｎｇａｎｄＥｔｃｈ－ｂａｃｋＳｉｌｉｃｏｎ－Ｏｎ－Ｉｎｓｕｌａｔｏｒ）制备了ＷＳｉ２栅和Ｓｉ栅４００７ＣＭＯＳ电路，在室温～２００℃的不同温度下测量了其Ｐ沟、Ｎ沟ＭＯＳＦＥＴ的亚阈特性曲线，分析了阈值电压和泄漏电流随温度的变化关系。     

功率合成电路在氮化镓放大器中的应用

针对氮化镓大功率放大器,由于传统1/4λ枝节线的电桥互耦造成放大器的直流自激和低频自激,在传统1/4λ传输枝节的Wilkinson电桥的基础上,结合氮化镓器件尺寸,设计出以3/4λ传输枝节的Wilkinson电桥为功率分配器/合成器。其输出端口尺寸为27.2mm。在8GHz～9GHz内,插入损耗<1dB,输出端口隔离度>14dB,端口回波损耗>9dB。利用实验室自制的SiC材料衬底的2.5mm栅宽GaN HEMT器件为放大单元,设计完成了两路合成放大器,在8GHz连续波条件下,放大器饱和输出功率为41.46dBm,合成效率为82.3%。通过分析发现,放大器合成效率的下降主要是由每路放大单元特性不一致和功率合成网络损耗所造成的。     

Low-loss y-branch waveguides designed by wavefront matching method and their application to a compact 1 x 32 splitter

A compact and low-loss Y-branch splitter is designed made with a high refractive-index difference waveguide and using the authors' wavefront matching method. The splitter was then fabricated using silica-based planar lightwave circuit technology. Excess loss was less than 0.2 dB per branch over a wide wavelength range of 1250 to 1650 nm     

一种超宽带印刷单极天线的研究

提出并研究了一种平面印刷单极天线,采用共面波导馈电,天线辐射体采用椭圆和带有对称枝节环的组合结构。着重研究如何通过调整内、外圆环枝节的长度,改变天线的谐振特性,从而实现天线在3.1～10.6GHz频率范围内回波损耗S11<-10dB,满足超宽带通信的要求。制作了实验模型,用矢量网络分析仪进行测试,与仿真结果比较取得较好一致性。     

基于缺陷地结构的三分支线定向耦合器设计

针对高特征阻抗微带传输线的线宽过窄难以加工实现以及器件耐功率性差的问题,提出了利用缺陷地结构(DGS)提高微带传输线特征阻抗的方法,在传统三分支线定向耦合器结构支节线下方接地平面设计蚀刻矩形DGS结构,实现高特征阻抗支节线,完成阻抗匹配,且实现了较大的工作带宽。采用电磁仿真软件进行建模仿真分析、参数优化并制作出实际电路进行测试验证,结果表明该定向耦合器在4.5~5.5 GHz频带内具有较低的插入损耗、较高的幅度和相位稳定度,性能良好,具有一定的实用价值。     

基于XeF_2硅刻蚀工艺的低阻硅衬底低损耗共面波导

在低阻硅(1~10Ω.cm)衬底上采用XeF2硅腐蚀工艺成功制备了长度为2 mm、结构尺寸为w/s=40/60μm间断悬浮和全悬浮两种结构的共面波导。SEM照片显示器件释放后的悬浮结构未出现粘附或破裂现象。通过WYKO三维形貌观察得到两种结构共面波导悬浮信号线最大翘曲量分别为10μm和16μm。微波性能测试结果表明两种悬浮结构共面波导在1~10 GHz频率范围内插入损耗分别低于4.5 dB/2 mm和3.2 dB/2 mm,远小于制作在低阻硅衬底上的普通共面波导插入损耗9.4 dB/2 mm;在1~3 GHz频率范围内插入损耗分别低于0.54 dB/2 mm和0.17 dB/2 mm,小于制作在高阻硅(1 400~1 500Ω.cm)衬底上普通共面波导的插入损耗0.55 dB/2 mm。     

2×2 optical waveguide switch with bow-tie electrode based oncarrier-injection total internal reflection in SiGe alloy

Based on the total internal reflection and the plasma dispersion effect of SiGe alloy, a 2×2 intersectional rib optical waveguide switch with bow-tie electrode has been proposed and fabricated for the wavelength of 1.3-μm operation. The thickness of the SiGe layer is 2.6 μm and the width is 9 μm. The branch angle of the switch is 2° and the bow-tie angle is 1.5°. The on-state crosstalk is -19.6 dB, the off-state extinction ratio is 38.5 dB and the off-state insertion loss is less than 1.70 dB. The switching time is about 180 ns     

Compact reflective-type phase-shifter MMIC for C-band using alumped-element coupler

The design and results of an ultra-compact single-load reflective-type monolithic-microwave integrated-circuit phase shifter at 6.2 GHz for a satellite radar system is presented in this paper, which has been fabricated using a commercial 0.6-μm GaAs MESFET process. A 3-dB 90° coupler with lumped elements enables significant circuit size reduction in comparison to former approaches applying microstrip branch line or Lange couplers. Phase control is enabled using MESFET varactors with capacitance control ratios (C_max/C_min ) of only four. Equations are derived to precisely describe the phase control ranges versus capacitance control ratios for different load configurations to allow efficient optimizations. Furthermore, the design tradeoff between low loss and high phase control range is discussed. Within a phase control range of 210°, a loss of 4.9 dB±0.9 dB and a 1-dB input compression point of higher than 5 dBm was measured for the designed phase shifter. The circuit size is less than 0.5 mm², which, to our knowledge, is the smallest reflective-type phase-shifter size reported to date     

PLZT film waveguide Mach-Zehnder electrooptic modulator

We report the numerical analysis and the fabrication of a reversed-ridge PLZT film waveguide. It is single-mode, has low transmission loss, and has large transverse cross-section suitable for efficient coupling to single-mode optical fibers. We used this structure to fabricate Mach-Zehnder (MZ) waveguide modulators. The field distribution in the channel and Y branch waveguides was calculated using a beam propagation method to analyze the modal profiles and the propagation loss. The reversed-ridge waveguides and the MZ structures were fabricated on r-sapphire substrates with a patterned ITO spacer film by sol-gel deposition. At 1.55 μm the propagation loss was 2.7 dB/cm. In the MZ, the half-wave modulation voltage was 8.5 V using 1.55 μm light and electrode length of 3.5 mm     

A Low-Loss Ku-Band Monolithic Analog Phase Shifter

A GaAs monolithic Ku-band analog phase shifter integrating 90° branch line coupler with planar varactor diodes has been fabricated for the first time. A phase shift of 109° +- 3° with an insertion loss of 1.8+-0.3 dB was measured from 16 to 18 GHz. A 360° phase shifter with 4.2+-0.9 dB insertion loss was realized in the same frequency range by connecting three phase-shifter chips in series. To our knowledge, this is the lowest insertion loss obtained by a 360° Ku-band phase shifter using monolithic circuits. In addition, hyperabrupt varactors using nonuniform doping profiles increased the phase shift by more than 30° and produced a more linear dependence of phase shift on control voltage.     

Laser-fabricated low-loss single-mode waveguiding devices in GaAs

A maskless laser etching technique was used to fabricate novel waveguides and waveguiding structures directly into the surface of GaAs/AlGaAs heterostructures. The modal and loss properties of these groove-defined structures have been measured as a function of waveguide geometry, and low-loss single-mode waveguides have been produced. The technique was used to fabricate various passive optical devices in a single processing step. Waveguide bend and branch losses were measured and are comparable to those in conventionally fabricated devices. Experimental results are described by simple theoretical models. The technique is attractive as a prototyping tool for developing and testing new integrated optic circuits