HCl/HF/CrO3溶液对InGaAs/InGaAsP的选择性湿法刻蚀——应用于楔形结构的制备

利用动态掩膜湿法腐蚀技术，研究了HCl/HF/CrO3溶液对与InP衬底晶格匹配的InxGa1－xAs1－yPy(y=0,0.2,0.4,0.6)材料的腐蚀特性．对于HCl(36wt%)/HF(40wt%)/CrO3(10wt%)的体积比为x∶0.5∶1的溶液，随着x由0增加到1.25，相应的腐蚀液对In0.53Ga0.47As/In0.72Ga0.28As0.6P0.4的选择性由42.4降到1.4；通过调节腐蚀液的选择性，在In0.72Ga0.28As0.6P0.4外延层上制备出了倾角从1.35°到35.9°的各种楔形结构；当x为0.025和1.25时，相应的In0.72Ga0.28As0.6P0.4腐蚀表面的均方根粗糙度分别为1.1nm和1.6nm．还研究了溶液的组分与InxGa1－xAs1－yPy(y=0,0.2,0.4)的腐蚀速率间的关系，并对腐蚀机理进行了分析．     

HF/CrO3溶液对AlGaAs的选择性湿法刻蚀应用于楔型结构的制备

利用动态掩膜腐蚀技术,研究了HF/CrO3腐蚀液对各种不同组分的AlxGa1-xAs(x＝0.3,0.5,0.65)的腐蚀速率及腐蚀表面形貌.随着HF(48wt%)/CrO3(33wt%)的体积比由0.01变化到0.138,相应的腐蚀液对Al0.8-Ga0.2As/Al0.3Ga0.7As的选择性由179降到8.6;通过调节腐蚀液的选择性,在Al0.3Ga0.7As外延层上制备出了倾角从0.32°到6.61°的各种斜面.当HF(48wt%)/CrO3(33wt%)的体积比为0.028时,Al组分分别为0.3、0.5和0.65时,相应的腐蚀表面的均方根粗糙度为1.8、9.1和19.3nm.另外,还分析了腐蚀机理与腐蚀表面形貌之间的关系.     

HF/CrO3溶液对AlGaAs的选择性湿法刻蚀应用于楔型结构的制备

利用动态掩膜腐蚀技术,研究了HF/CrO3腐蚀液对各种不同组分的AlxGa1-xAs(x＝0.3,0.5,0.65)的腐蚀速率及腐蚀表面形貌.随着HF(48wt%)/CrO3(33wt%)的体积比由0.01变化到0.138,相应的腐蚀液对Al0.8-Ga0.2As/Al0.3Ga0.7As的选择性由179降到8.6;通过调节腐蚀液的选择性,在Al0.3Ga0.7As外延层上制备出了倾角从0.32°到6.61°的各种斜面.当HF(48wt%)/CrO3(33wt%)的体积比为0.028时,Al组分分别为0.3、0.5和0.65时,相应的腐蚀表面的均方根粗糙度为1.8、9.1和19.3nm.另外,还分析了腐蚀机理与腐蚀表面形貌之间的关系.     

InP基一镜斜置三镜腔型光电探测器理论分析及实验研究

介绍了一种新型长波长InP基一镜斜置三镜腔型（OMITMiC）光电探测器，并对其进行了数值模拟。介绍了该光电探测器的两项关键制备工艺。首先，利用动态掩膜湿法腐蚀技术，通过调节HCl：HF：CrO3腐蚀溶液的选择比。在与InP晶格匹配的In0.72Ga0.28As0.6P0.4外延层上制备出了不同倾角的楔形结构。其次，利用选择性湿法腐蚀技术，通过FeCl3；H2O溶液对In0.53Ga0.47As牺牲层的腐蚀，制备出了具有InP／空气隙的高反射率分布式布拉格反射镜（DBR）。     

半导体激光器阵列隔离槽的湿法腐蚀

研究了几种腐蚀液对半导体激光器阵列外延材料的腐蚀过程,其中HF(40%)/CrO3(33wt%)腐蚀液比较适合,用扫描电子显微镜(SEM)对其腐蚀情况进行了分析,并给出了利用这种腐蚀液进行腐蚀的半导体激光器阵列隔离槽的图像.通过调节HF/CrO3腐蚀液的体积比(从0.02到0.2),确定了AlxGa1-xAs组分渐变材料的腐蚀条件(室温23℃,腐蚀时间4min)以及最佳配比(体积比为0.1).利用这种腐蚀液得到的腐蚀图形可以满足激光器阵列的要求.     

半导体激光器阵列隔离槽的湿法腐蚀

研究了几种腐蚀液对半导体激光器阵列外延材料的腐蚀过程,其中HF(40 %) /CrO3 (33wt%)腐蚀液比较适合,用扫描电子显微镜(SEM)对其腐蚀情况进行了分析,并给出了利用这种腐蚀液进行腐蚀的半导体激光器阵列隔离槽的图像.通过调节HF/CrO3 腐蚀液的体积比(从0 0 2到0 2 ) ,确定了AlxGa1-xAs组分渐变材料的腐蚀条件(室温2 3℃,腐蚀时间4min)以及最佳配比(体积比为0 1) .利用这种腐蚀液得到的腐蚀图形可以满足激光器阵列的要求.     

气态源分子束外延生长扩展波长InGaAs探测器性能分析

从理论与实验两方面对截止波长为1.7μm(x=0.53),1.9μm(x=0.6)和2.2μm(x=0.7)p in InxGa1-xAs探测器性能进行了研究.对探测器暗电流的研究结果表明,扩展波长In0.6Ga0.4As,In0.7Ga0.3As探测器在反向偏置低压区,欧姆电流占据主导地位;在反向偏置高压区,缺陷隧穿电流占主导地位;且扩展波长In0.6Ga0.4As,In0.7Ga0.3As探测器的暗电流比In0.53Ga0.47As探测器增加较大.对探测器R0A随温度及i层载流子浓度变化关系的研究结果表明,在热电制冷温度下探测器性能可得到较大提高,i层的轻掺杂可使探测器的R0A得到改善.     

采用InGaAs或InAlAs缓冲层的高In组分InGaAs探测器结构材料特性

利用气态源分子束外延在InP衬底上生长了具有InxGa1-xAs或InxAl1-xAs连续递变缓冲层的高In组分In0.78Ga0.22As探测器结构.通过原子力显微镜、X射线衍射、透射电子显微镜和光致发光对它们的特性进行了表征和比较.结果表明,具有InxGa1-xAs或InxAl1-xAs缓冲层的结构都能获得较平整的...     

GaAs MISFET制备中柠檬酸/双氧水溶液对GaAs/AlxGa1-xAs结构的选择湿法腐蚀

用α台阶仪和原子力显微镜(AFM)研究了不同体积比的柠檬酸(50%)/双氧水溶液对GaAs/AlxGa1-xAs系统的选择湿法腐蚀特性,对AlxGa1-xAs停止层的组分和腐蚀液体积比进行了优化.当腐蚀液体积比在1.5∶1到2∶1范围时获得了最好的选择腐蚀效果.在25℃.温度条件下,当腐蚀液体积比为1.5∶1时,对Al摩尔分数x为0.2、0.3和1的GaAs/AlxGa1-xAs系统腐蚀比分别为45、74和大于200,表面腐蚀形貌均匀平整.将这种选择腐蚀技术用于GaAsMISFET的栅槽工艺,获得了良好的阈值电压均匀性.     

失配异质结构InGaAs/InP的MOCVD生长

基于延展波长(截止波长2.2μm)InGaAs-PIN光电探测器进行了失配异质结构InxGa1-xAs(x=0.72)/InP的MOCVD外延生长研究。采用宽带隙组分梯度渐变的InAlAs作为缓冲层和顶层,通过生长优化,获得了满足器件要求的外延材料。     

Performance improvement in tensile-strained In/sub 0.5/Al/sub 0.5/As/In/sub x/Ga/sub 1-x/As/In/sub 0.5/Al/sub 0.5/As metamorphic HEMT

This paper proposes a In/sub 0.5/Al/sub 0.5/As/In/sub x/Ga/sub 1-x/As/In/sub 0.5/Al/sub 0.5/As (x=0.3-0.5-0.3) metamorphic high-electron mobility transistor with tensile-strained channel. The tensile-strained channel structure exhibits significant improvements in dc and RF characteristics, including extrinsic transconductance, current driving capability, thermal stability, unity-gain cutoff frequency, maximum oscillation frequency, output power, power gain, and power added efficiency.     

Very low-noise Al/sub 0.3/Ga/sub 0.7/As/Ga/sub 0.65/In/sub 0.35/As/GaAs single quantum-well pseudomorphic HEMTs

AlGaAs/GaInAs/GaAs pseudomorphic HEMTs with an InAs mole fraction as high as 35% in the channel has been successfully fabricated. The device exhibits a maximum extrinsic transconductance of 700 mS/mm. At 18 GHz, a minimum noise figure of 0.55 dB with 15.0 dB associated gain was measured. At 60 GHz, a minimum noise figure as low as 1.6 dB with 7.6 dB associated gain was also obtained. This is the best noise performance yet reported for GaAs-based HEMTs.<>     

A 12 /spl times/ 12 In/sub 0.53/Ga/sub 0.47/As-In/sub 0.52/Al/sub 0.48/As avalanche photodiode array

We report a 12 /spl times/ 12 In/sub 0.53/Ga/sub 0.47/As-In/sub 0.52/Al/sub 0.48/As avalanche photodiode (APD) array. The mean breakdown voltage of the APD was 57.9 V and the standard deviation was less than 0.1 V. The mean dark current was /spl sim/2 and /spl sim/300 nA, and the standard deviation was /spl sim/0.19 and /spl sim/60 nA at unity gain (V/sub bias/ = 13.5 V) and at 90% of the breakdown voltage, respectively. External quantum efficiency was above 40% in the wavelength range from 1.0 to 1.6 /spl mu/m. It was /spl sim/57% and /spl sim/45% at 1.3 and 1.55 /spl mu/m, respectively. A bandwidth of 13 GHz was achieved at low gain.     

Al/sub 0.3/Ga/sub 0.7/As/In/sub x/Ga/sub 1-x/As (0/spl les/x/spl les/0.25) doped-channel field-effect transistors (DCFET's)

The properties of both lattice-matched and strained doped-channel field-effect transistors (DCFET's) have been investigated in AlGaAs/In/sub x/Ga/sub 1-x/As (0/spl les/x/spl les/0.25) heterostructures with various indium mole fractions. Through electrical characterization of grown layers in conjunction with the dc and microwave device characteristics, we observed that the introduction of a 150-/spl Aring/ thick strained In/sub 0.15/Ga/sub 0.85/As channel can enhance device performance, compared to the lattice-matched one. However, a degradation of device performance was observed for larger indium mole fractions, up to x=0.25, which is associated with strain relaxation in this highly strained channel. DCFET's also preserved a more reliable performance after biased-stress testings.<>     

Morphological and electrical characterization of SixCryCzBv thin films

Si_xCr_yC_zB_v thin films with several compositions have been studied for integration of high precision resistors in 0.8 μm BICMOS technology. These resistors, integrated in the back-end of line, have the advantage to provide high level of integration and attractive electrical behavior in temperature, for analog devices. The film morphology and the structure have been investigated through transmission electron microscopy analysis and have been then related to the electrical properties on the base of the percolation theory. According to this theory, and in agreement with experimental results, negative thermal coefficient of resistance (TCR) has been obtained for samples with low Cr content, corresponding to a crystalline volume fraction below the percolation threshold.Samples with higher Cr content exhibit, instead, a variation of the TCR as a function of film thickness: negative TCR values are obtained for thickness lower than 5 nm, corresponding to a crystalline volume fraction below the percolation threshold; positive TCR are obtained for larger thickness, indicating the establishment of a continuous conductive path between the Cr rich grains. This property seems to be determinant in order to assure the possibility to obtain thin film resistors almost independent on the temperature.     

Highly linear Al/sub 0.3/Ga/sub 0.7/N-Al/sub 0.05/Ga/sub 0.95/N-GaN composite-channel HEMTs

We report an Al/sub 0.3/Ga/sub 0.7/N-Al/sub 0.05/Ga/sub 0.95/N-GaN composite-channel HEMT with enhanced linearity. By engineering the channel region, i.e., inserting a 6-nm-thick AlGaN layer with 5% Al composition in the channel region, a composite-channel HEMT was demonstrated. Transconductance and cutoff frequencies of a 1 /spl times/100 /spl mu/m HEMT are kept near their peak values throughout the low- and high-current operating levels, a desirable feature for linear power amplifiers. The composite-channel HEMT exhibits a peak transconductance of 150 mS/mm, a peak current gain cutoff frequency (f/sub T/) of 12 GHz and a peak power gain cutoff frequency (f/sub max/) of 30 GHz. For devices grown on sapphire substrate, maximum power density of 3.38 W/mm, power-added efficiency of 45% are obtained at 2 GHz. The output third-order intercept point (OIP3) is 33.2 dBm from two-tone measurement at 2 GHz.     

Comparison between Pt/TiO2/Pt and Pt/TaOX/TaOY/Pt based bipolar resistive switching devices

Nonvolatile memories have emerged in recent years and have become a leading candidate towards replacing dynamic and static random-access memory devices. In this article, the performances of TiO₂ and TaO₂ nonvolatile memristive devices were compared and the factors that make TaO₂ memristive devices better than TiO₂ memristive devices were studied. TaO₂ memristive devices have shown better endurance performances (10⁸ times more switching cycles) and faster switching speed (5 times) than TiO₂ memristive devices. Electroforming of TaO₂ memristive devices requires~4.5 times less energy than TiO₂ memristive devices of a similar size. The retention period of TaO₂ memristive devices is expected to exceed 10 years with sufficient experimental evidence. In addition to comparing device performances, this article also explains the differences in physical device structure, switching mechanism, and resistance switching performances of TiO₂ and TaO₂ memristive devices. This article summarizes the reasons that give TaO₂ memristive devices the advantage over TiO₂ memristive devices, in terms of electroformation, switching speed, and endurance.     

Electrooptic ferroelectric Na/sub 0.5/K/sub 0.5/NbO/sub 3/ films

We report on waveguiding and electrooptic properties of epitaxial Na/sub 0.5/K/sub 0.5/NbO/sub 3/ films grown by radio-frequency magnetron sputtering on Al/sub 2/O/sub 3/(11_02) single crystal substrates. High optical waveguiding performance has been demonstrated in infrared and visible light. The in-plane electrooptic effect has been recorded in transmission using a transverse geometry. At dc fields, the effective linear electrooptic coefficient was determined to 28 pm/V, which is promising for modulator applications.