采用AI／TaN叠层电极提高Si基GePIN光电探测器的性能

金属与Ge材料接触由于存在强烈的费米钉扎效应,导致金属电极与n型Ge接触引入较大的接触电阻,限制了si基Ge探测器响应带宽．本文报道了在SOI衬底上外延Ge单晶薄膜并制备了不同台面尺度的GePIN光电探测器．对比了电极分别为金属Al和A1／TaN叠层的具有相同器件结构的SOI基GePIN光电探测器的暗电流、响应度以及响应带宽等参数．发现在Al与Ge之间增加一薄层TaN可有效减小n型Ge的接触电阻,将台面直径为24um的探测器在1．55um的波长和-1V偏压下的3dB响应带宽提高了4倍．同时,器件暗电流减小一个数量级,而响应度提高了2倍．结果表明,采用TaN薄层制作金属与Ge接触电极,可有效钝化金属与Ge界面,减轻费米钉扎效应,降低金属与n-Ge接触的势垒高度,因而减小接触电阻和界面复合电流,提高探测器的光电性能．     

MSM结构Mg0.2Zn0.8O可见盲光电探测器

采用射频磁控溅射,通过传统的紫外曝光和湿法腐蚀的方法,制备了不同电极间距的金属-半导体-金属(MSM)结构Mg0.2Zn0.8O可见盲光电探测器.研究了器件的暗电流和响应度随电极间距的变化关系,当施加的电压没有达到贯穿电压的时候,暗电流和响应度均随着电极间距的增加而减小,并对其具体的机制进行了研究.     

金属与半导体Ge欧姆接触制备、性质及其机理分析

金属与Ge材料接触时界面处存在着强烈的费米钉扎效应, 尤其与n型Ge形成的欧姆接触的比接触电阻率高, 是制约Si基Ge器件性能的关键因素之一. 本文对比了分别采用金属Al和Ni 与Si衬底上外延生长的p型Ge和n型Ge材料的接触特性. 发现在相同的较高掺杂条件下, NiGe与n型Ge可形成良好的欧姆接触, 其比接触电阻率 较 Al接触降低了一个数量级, 掺P浓度为2×10¹⁹ cm^-3时达到1.43×10^-5 Ω·cm². NiGe与p型Ge接触和Al接触的比接触电阻率相当, 掺B浓度为4.2×10¹⁸ cm^-3时达到1.68×10^-5 Ω·cm². NiGe与n型Ge接触和Al电极相比较, 在形成NiGe过程中, P杂质在界面处的偏析是其接触电阻率降低的主要原因. 采用NiGe作为Ge的接触电极在目前是合适的选择. 关键词： 金属与Ge接触性质 NiGe 比接触电阻率     

高性能SOI基GePIN波导光电探测器的制备及特性研究

本文报道了在SOI衬底上外延高质量单晶Ge薄膜并制备高性能不同尺寸Ge PIN波导光电探测器.通过采用原子力显微镜、X射线衍射、拉曼散射光谱表征外延Ge薄膜的表面形貌、晶体质量以及应变参数,结果显示外延Ge薄膜中存在约0.2%左右的张应变,且表面平整,粗糙度为1.12 nm.此外,通过暗电流、光响应度以及3 dB带宽的测试来研究波导探测器的性能,结果表明尺寸为4μm×20μm波导探测器在-1 V的反向偏压下暗电流密度低至75 mA/cm~2,在1.55μm波长处的响应度为0.58 A/W,在-2 V的反向偏压下的3 dB带宽为5.5 GHz.     

InGaAs-MSM光电探测器设计与仿真研究

对基于InGaAs材料体系的金属 半导体 金属（metal semiconductor metal,MSM）光电探测器进行设计,并对其暗电流、光电流、电容以及截止频率等性能参数进行仿真。通过添加InAlAs肖特基势垒增强层,将探测器的暗电流减小到了pA量级。仿真结果表明,探测器在光照下有明显的光响应,通过合理设计器件结构,探测器的工作频率可以达到1.5 THz。制备了探测器样品,并对其暗电流和光响应进行了测试,测试结果与仿真结果基本吻合。     

半导体量子器件物理讲座第七讲半导体异质结光电探测器

光电探测器是一类用于接收光波并转变为电信号的专门器件，文章描述了PIN光电二极`管雪崩光电二极管、MSM（金属－半导体－金属）光电二极管的器件结构和工作原理，并对它们的响应度、噪声、带宽等特性进行了讨论，这类器件已在光通信、光信息处理等许多系统中得到广泛的应用。     

低暗电流InGaAs-MSM光电探测器

MSM(金属-半导体-金属)型光电探测器的较低寄生电容和高带宽的特点使得其应用广泛,可用于空间通信、遥感等多方面,但暗电流偏大仍是制约其发展的重要因素.为此,本文研制了100×100μm2面积的InGaAs-MSM光电探测器,通过设计InAlGaAs/InGaAs短周期超晶格和InAlAs肖特基势垒增强结构,将器件暗电流密度降至0.6pA/μm2(5V偏置),改善了目前同类器件的信噪比.对器件光电参数进行了表征:3dB带宽6.8GHz,上升沿58.8ps,1550nm波段响应度0.55A/W,光吸收区域外量子效率88%.分析了短周期超晶格和肖特基势垒增强层对暗电流的抑制机理.     

超薄介质插层调制的氧化铟锡/锗肖特基光电探测器

本文通过在氧化铟锡(indium tin oxide, ITO)透明电极和锗(germanium, Ge)之间引入超薄氧化物介质层以调节其接触势垒高度,制备出低暗电流、高响应度的锗肖特基光电探测器.比较研究了采用不同种类介质Al_2O_3和MoO_3,以及不同掺杂浓度的锗和硅衬底上外延锗材料制作的ITO/Ge肖特基二极管特性.发现2 nm厚的Al_2O_3插层可有效提高ITO与n-Ge和i-Ge的接触势垒高度,而MoO_3插层对ITO与不同Ge材料的接触势垒高度影响不明显. ITO/Al_2O_3/i-Ge探测器由于其增大的势垒高度表现出性能最佳,暗电流(–4 V)密度低至5.91 mA/cm~2, 1310 nm波长处光响应度高达4.11 A/W.而基于硅基外延锗(500 nm)材料制作的ITO/Al_2O_3/Ge-epi光电探测器的暗电流(–4 V)密度为226.70 mA/cm~2, 1310 nm处光响应度为0.38 A/W.最后,使用二维位移平台对ITO/Al_2O_3/i-Ge光电探测器进行了单点成像实验,在1310 nm, 1550 nm两个波段得到了清晰可辨的二维成像图.     

PIN光电探测器的建模与仿真分析

为了优化PIN光电探测器响应特性,首先依据载流子速率方程,并考虑芯片寄生参量和封装寄生参量,建立光电探测器的等效电路模型。然后仿真分析了反偏电压、I区宽度、光敏面、芯片寄生电阻和电容、封装寄生电阻、电容和电感对光电探测器脉冲响应特性和频率响应特性的影响。结果表明:通过增大反偏电压,减小光敏面和寄生参量(芯片寄生电容和电阻,封装寄生电容和电阻),选取合适的I区宽度,利用引线电感的谐振效应现象,可以抑制脉冲响应波形畸变,提高频率响应带宽。     

ZnO基紫外探测器的制作与研究

利用新型的等离子体辅助金属有机化学气相沉积(P-MOCVD)系统在蓝宝石、硅等衬底上生长出具有单一c轴取向、高阻的ZnO薄膜,利用添加的等离子体发生装置,进行氮掺杂获得高阻ZnO薄膜。利用ZnO的宽禁带与高光电导特性,结合MSM(金属-半导体-金属)结构器件响应度高、速度快、随偏压变化小、工艺简单、易于单片集成等优点,制作了ZnO基紫外探测器,器件规格为80 μm×100μm,电极为叉指式电极。测试中采用500 W的氙灯做测试光源,探测器的Ⅰ-Ⅴ特性曲线显示;正向偏压下探测器的暗电流及光照电流与外加偏压呈线性增长。不同波长下的响应曲线显示:探测器对紫外波段有响应,响应峰值在375nm附近。     

Hybrid Integration of 1 × 12 Metal-Semiconductor-Metal Photodetector and Polyimide Waveguide Array

We report here a demonstration of hybrid integration of a 1 × 12 metal-semiconductor-metal (MSM) photodetector array and polyimide channel waveguides via 45° total-internal-reflection (TIR) micro-couplers. The two-layer polyimide waveguide array was constructed using Ultradel 9120D for the core and Ultradel 9020 for the lower cladding layer. The coupling loss and propagation loss of the waveguide are 0.2dB and 0.21 dB/cm, respectively. The cross talk of the adjacent channels is -32 dB. The MSM photodetector array was fabricated on a semi-insulated GaAs wafer. The photodetectors are integrated to operate in the conventional vertical illumination mode. We measured the external quantum-efficiency and 3 dB bandwidth of the integrated MSM photodetectors at 0.4 A/W and 2.648 GHz, respectively. The aggregate 3 dB bandwidth of the 12-channel integrated system is 32 GHz.     

High-speed waveguide-integrated Ge/Si avalanche photodetector

Waveguide-integrated Ge/Si heterostructure avalanche photodetectors(APDs) were designed and fabricated using a CMOS-compatible process on 8-inch SOI substrate. The structure of the APD was designed as separate-absorption-chargemultiplication(SACM) using germanium and silicon as absorption region and multiplication region, respectively. The breakdown voltage(V_b) of such a device is 19 V at reverse bias and dark current appears to be 0.71 μA at 90% of the V_b. The device with a 10-μm length and 7-μm width of Ge layer shows a maximum 3-dB bandwidth of 17.8 GHz at the wavelength of 1550 nm. For the device with a 30-μm-length Ge region, gain-bandwidth product achieves 325 GHz.     

10 Gbit/s Silicon modulator and germanium detector chip-to-chip optical link

Experimental results of a high-speed silicon optical modulator based on carrier depletion in a pipin diode and Germanium photodetectors are presented. 10 Gbit/s data transmission is obtained for both optoelectronic devices, with for the optical modulator an extinction ratio (ER) higher than 8 dB and insertion loss (IL) lower than 6 dB and for Ge photodetector, a zero-bias operating at 10 Gbit/s. Finally, a 10 Gbit/s optical link combining Si modulator and Ge photodetector is demonstrated.     

背入射Au/ZnO/Al结构肖特基紫外探测器

设计制作了一种Au/ZnO/Al结构的紫外探测器,光的入射方式采用背入射式。ZnO薄膜是用磁控溅射在蓝宝石衬底上制备的。I-V测试表明:Au与ZnO形成了肖特基接触。得到探测器的光响应峰值在352nm,截止边为382nm,可见抑制比达一个量级。由于该探测器是一种垂直结构器件,对于进一步实现ZnO紫外探测器阵列及单光子探测有很好的研究价值。     

Study on the spectral response of the Schottky photodetector of GaN

The Schottky photodetector was fabricated on GaN epilayers grown by metalorganic chemical vapour deposition (MOCVD). The spectral response of the Schottky photodetector was characterized. A new model is proposed to interpret the characteristic of the spectral response curve of the Schottky photodetectors by introducing a penetrating distance of an incident light at a certain wavelength in the current continuity equation and the interface recombination at the metal--semiconductor rectifying contact. The expressions for the spectral response of the Schottky photodetector are deduced and used successfully to fit the experimental data.     

The photodetector of Ge nanocrystals/Si for 1.55 μm operation deposited by pulsed laser deposition

The photodetector properties of a Ge nanocrystals detector fabricated by pulsed laser deposition and in situ rapid thermal annealing treatment at 600 °C have been studied. Strong optical absorption and photocurrent response of the detector are measured in the wavelength range 1.3-1.55 μm. The detector possesses a low dark current of 61.4 nA and a photocurrent responsivity of 56 mA/W at the reverse bias 5 V. The external quantum efficiency at 1.55 μm is estimated to be 15%. The stop wavelength of absorption spectra extends to 1.65 μm. It indicates that these kind of Ge nanocrystals devices can be used as a 1.3-1.55 μm near infrared detector.     

Comparative studies of Ge and Si p-channel metal-oxide-semiconductor field-effect-transistors with HfSiON dielectric and TaN metal gate

Ge and Si p-channel metal--oxide--semiconductor field-effect-transistors (p-MOSFETs) with hafnium silicon oxynitride (HfSiON) gate dielectric and tantalum nitride (TaN) metal gate are fabricated. Self-isolated ring-type transistor structures with two masks are employed. W/TaN metal stacks are used as gate electrode and shadow masks of source/drain implantation separately. Capacitance--voltage curve hysteresis of Ge metal--oxide--semiconductor (MOS) capacitors may be caused by charge trapping centres in GeO7340Q, 7325http://cpb.iphy.ac.cn/CN/10.1088/1674-1056/19/5/057302https://cpb.iphy.ac.cn/CN/article/downloadArticleFile.do?attachType=PDF&id=111774Ge substrate, transistor, HfSiON, hole mobilityProject supported by the National Basic Research Program of China (Grant No.~2006CB302704).Ge and Si p-channel metal--oxide--semiconductor field-effect-transistors (p-MOSFETs) with hafnium silicon oxynitride (HfSiON) gate dielectric and tantalum nitride (TaN) metal gate are fabricated. Self-isolated ring-type transistor structures with two masks are employed. W/TaN metal stacks are used as gate electrode and shadow masks of source/drain implantation separately. Capacitance--voltage curve hysteresis of Ge metal--oxide--semiconductor (MOS) capacitors may be caused by charge trapping centres in GeO$_{x}$ ($1Ge;substrate;transistor;HfSiON;hole;mobilityGe and Si p-channel metal-oxide-semiconductor field-effect-transistors(p-MOSFETs) with hafnium silicon oxynitride(HfSiON) gate dielectric and tantalum nitride(TaN) metal gate are fabricated.Self-isolated ring-type transistor structures with two masks are employed.W/TaN metal stacks are used as gate electrode and shadow masks of source/drain implantation separately.Capacitance-voltage curve hysteresis of Ge metal-oxide-semiconductor(MOS) capacitors may be caused by charge trapping centres in GeOx(1 < x < 2).Effective hole mobilities of Ge and Si transistors are extracted by using a channel conductance method.The peak hole mobilities of Si and Ge transistors are 33.4 cm2/(V.s) and 81.0 cm2/(V.s),respectively.Ge transistor has a hole mobility 2.4 times higher than that of Si control sample.     

Optical saturation characteristics of dual-and single-injection Ge-on-Si photodetectors

The optical saturation characteristics in the germanium-on-silicon(Ge-on-Si) photodetector are studied for the first time, to the best of our knowledge. The relationship between the optical saturation characteristics and the optical field distribution in the Ge layer is illustrated by the simulation. This theory is verified by comparative experiments with single-injection and dual-injection structures. The dual-injection photodetector with a more balanced and uniform optical field distribution has a 13% higher responsivity at low optical power and 74.4%higher saturation current at 1550 nm. At higher optical power, the bandwidth of the dual-injection photodetector is five times larger than that of the single-injection photodetector.