低暗电流InGaAs金属－半导体－金属光电探测器

首次采用双重肖特基势垒增强层技术，制作了ＩｎＧａＡｓ金属－半导体－金属光电探测器。实验结果表明：具有１５ｎｍ的ｐ－ＩｎＰ和１００ｎｍ的ＩｎＰ双重势垒增强层的器件，极大地减小了暗电流，最小达４．７ｎＡ（１０Ｖ），证明这是一种减小金属－半导体－金属光电探测器暗电流的有效途径     

低喑电流InGaAs金属—半导体—金属光电探测器

首次采用双重肖特基势垒增强层技术，制作了ＩｎＧａＡｓ金属－半导体－金属光电探测器。实验结果表明：具有１５ｍｍ的ｐ－ＩｎＰ和１００ｎｍ的ＩｎＰ双重势垒增强层的器件，极大地减少了暗电流，最小达４．７ｎＡ（１０Ｖ），证明这是一种减小金属－半导体－金属８光电探测器暗电流的有效途径。     

高锗组分PIN锗硅光电探测器设计与模拟

介绍了Si1-xGex合金材料在制作新型光电子器件方面的重要作用,描述了应变SiGe层的特性,包括其临界厚度与Ge组分的关系、能带变窄、折射率增加,以及应变SiGe层的亚稳态特性.设计了应变锗硅缓冲层上的高Ge组分PIN光电探测器的外延材料和结构,采用Silvaco软件分别对光电探测器的器件结构、光谱响应、响应电流及其随入射光功率的变化、器件的暗电流进行了模拟,结果显示,探测器有源区面积增大,其响应电流也增大,且暗电流比其响应电流小6～8个数量级;探测器的响应时间约为3.8x10-9s;探测器在850nm左右具有较好的光响应;这些结果都比较理想.采用L-edit软件设计了该光电探测器的结构,最后对研究结果做出总结.     

一种肖特基势垒强型N-AlGaN基 MSM日盲紫外光电探测器

研制一种以薄的高阻AlGaN覆盖层作为肖特基势垒增强层的N?AlGaN基金属?半导体?金属（MSM）日盲紫外光电探测器。与无覆盖层的参考器件相比,覆盖高阻AlGaN层后探测器的暗电流大幅度减小。在5 V偏压下,覆盖高阻AlGaN层的光电探测器的暗电流为1.6 pA,响应度为22.5 mA/W,日盲紫外抑制比大于103,探测率为6.3×1010 cm·Hz1/2/W。     

基于湿法腐蚀工艺的高性能黑硅光电探测器

采用基于硝酸/氢氟酸/磷酸/硫酸混合液的湿法腐蚀工艺,实现了高吸收效率的黑硅结构的制备与工艺集成,获得了具有近红外响应增强效果的黑硅PIN光电探测器,并与未集成黑硅的PIN光电探测器的性能参数进行了对比测试.测试结果显示,黑硅光电探测器在1 060 nm波长下的响应度达到0.69 A/W(量子效率80.7％),较未集成黑硅的器件提高了 116％;黑硅探测器暗电流小于8 nA,响应时间小于8 ns,电容小于9 pF,与未集成黑硅的器件相当.得益于工艺兼容性,所采用的黑硅技术具有广泛应用于硅基近红外PIN,APD,SPAD,SPM等光电探测器的潜力,可显著提高器件的响应率、量子效率、响应速度、击穿电压温度系数等性能.     

基于CVD单层MoS_2 FET的光电探测器北大核心

通过化学气相沉积(CVD)工艺在SiO_2/Si衬底生长出MoS_2材料,对材料进行喇曼光谱表征,验证了单层MoS_2的存在;基于CVD生长的单层MoS_2完成了晶圆级背栅场效应晶体管(FET)光电探测器的工艺研发;对MoS_2 FET器件进行了电学特性表征,开关比可达到105数量级,场效应迁移率约为1 cm2·V-1·s-1,栅极漏电流为10-10 A数量级;对MoS2FET器件的光电特性进行了表征,该光电探测器具有普通光电导探测器的基本光电特性,其光电流随光照强度的增强以及源漏电压的增加而增加,同时由于栅极的调制提高了光电探测器的灵活性。通过控制栅极电压能够控制MoS2FET光电探测器的暗电流大小,实现对探测器η参数的有效调制。最后通过器件能带图对MoS_2 FET光电探测器的光电特性进行了阐释,为其走向实际应用奠定了理论基础。     

一种肖特基势垒增强型N-AlGaN基MSM日盲紫外光电探测器

研制一种以薄的高阻Al Ga N覆盖层作为肖特基势垒增强层的N-Al Ga N基金属-半导体-金属(MSM)日盲紫外光电探测器。与无覆盖层的参考器件相比,覆盖高阻Al Ga N层后探测器的暗电流大幅度减小。在5 V偏压下,覆盖高阻Al Ga N层的光电探测器的暗电流为1.6 p A,响应度为22.5 m A/W,日盲紫外抑制比大于103,探测率为6.3×1010cm·Hz1/2/W。     

极低暗电流InGaAs MSM-PD的光电特性研究

本文首次采用双重肖特基势垒增强层技术，制作了InGaAsMSMS－PD光电探测器．实际结构表明：具有15nm的P－InP和100nmInP双重势垒增强层的器件极大地减小了暗电流，器件的暗电流均小于10nA，响应度为0．83A／W，FWHM为70ps，证明这是一种减小MSM－PD暗电流的有效设计方法．     

一种低暗电流高响度InGaAs/InP pin光电探测器

分析了InGaAs/InP pin光电探测器暗电流和响应度的影响因素,并对MOCVD外延工艺以及器件结构进行优化,从而提高器件响应度和降低暗电流。采用低压金属有机化学气相沉积设备(LP-MOCVD)成功制备了InGaAs/InP pin光电探测器,得到了高质量的晶体材料,InGaAs吸收层的背景浓度低于4×1014 cm-3。利用扩Zn工艺制作出感光区直径为70μm的平面光电探测器。测量结果显示,在反偏电压为5 V时,暗电流小于0.05 nA,电容约为0.4 pF。此外,在1 310 nm激光的辐照下,器件的响应度可达0.96 A/W以上。     

含有超晶格电子势垒的In0.83Ga0.17As探测器暗电流仿真和验证

为了获得In0.83Ga0.17As探测器的暗电流机制,采用了TCAD软件对吸收层中含有和不含有超晶格电子势垒的p-i-n结构探测器暗电流特性进行仿真,并开展了器件验证,结果表明,超晶格势垒可以调整器件的能带结构,改变载流子传输特性,降低SRH复合,从而降低器件的暗电流,仿真结果与实验结果吻合;并在此基础上,分析了势垒位置和周期变化对暗电流的影响,提出了进一步降低器件暗电流的超晶格电子势垒优化结构。     

Hydrogen desorption and diffusion in PECVD silicon nitride. Application to passivation of CMOS active pixel sensors

Presented either as a source or as a barrier to hydrogen, plasma deposited silicon nitride can impact microelectronic device performances. The objective of this paper is to clarify the hydrogen behavior in silicon nitride in order to optimize film characteristics for each microelectronic application. A design of experiments methodology was used to statistically discriminate films properties which govern hydrogen diffusion and desorption from PECVD silicon nitride. Finally, we confirm, thanks to trials on CMOS active pixel sensor devices and dark current measurements, the role of the SiN passivation layer on Si remaining defect and we propose an optimized passivation stack.     

An a-Si:H/a-Si,Ge:H bulk barrier phototransistor with a-SiC:Hbarrier enhancement layer for high-gain IR optical detector

The design and fabrication of a high-gain amorphous silicon/amorphous silicon germanium (a-Si:H/a-Si,Ge:H) bulk barrier phototransistor for infrared light detection applications are reported. The a-Si,Ge:H material featured a lower energy gap and is suitable for the absorption of longer wave light, but it also leads to a low breakdown voltage and high dark current. An additional a-SiC:H thin-film layer was used at the collector/base interface in the conventional amorphous bulk barrier phototransistor to enhance the function of the bulk barrier and obtain high optical gain     

用于光纤通信的硅光电探测器的研制

根据光纤入户（FTTH）的应用特点,选用外延层厚度和电阻率各不相同的三种硅外延片,研制了用于FTTH的PIN硅光电探测器,并与硅单晶材料的PN结光电二极管进行了全程比对.测量结果表明,PIN探测器的暗电流可达10-11A量级,响应时间为2 ns.分析了Ⅰ层厚度和电阻率对探测器件暗电流、结电容和响应时间的影响及引起特性差别的原因,为设计能满足光纤通信要求的光电探测器提供了依据.     

Effect of parylene layer on the performance of OLED

An organic light-emitting device structure with a thin parylene layer deposited by low-temperature chemical vapour deposition at the anode-organic interface was fabricated. Such a structure gives higher luminescence efficiency when operated at the same current density compared to one without the parylene layer. In addition, the devices with a thin parylene layer also show a smaller number and smaller size dark non-emissive areas, slower growth rate of the dark areas and a longer device lifetime. The modified surface of the indium tin oxide (ITO) shows an increased work function compared to that of the ITO surface alone and a reduced surface roughness, which contributes to the device performance improvement. The parylene layer is a conformal coating on the ITO surface, which could significantly stabilise the interface leading to a more uniform current density. It also provides a good barrier for blocking oxygen and moisture diffusion and hence reducing dark spot occurrence.     

Theoretical study of the response of InGaAsmetal-semiconductor-metal photodetectors

We present a theoretical investigation of the response of metal-semiconductor-metal (MSM) photodetectors made of InGaAs lattice-matched to InP using a two-dimensional drift-diffusion model with a thermionic-field emission boundary condition for the heterojunctions. The effect of including a top InAlAs layer to increase the effective barrier height of the metal fingers on the InGaAs active layer is thoroughly examined and found to limit the collection of the photocurrent signal due to the electron and hole barriers that it forms with InGaAs. Due to the thickness and height of the InAlAs barrier layer in existing designs, the tunneling current obtained from the model is found to be negligibly small to significantly affect the output signal current. In an attempt to obtain a better response, different design structures including one where a quasi-Schottky contact is utilized are studied and their speed of response, breakdown voltage, and dark current are compared to that of the usual InGaAs device     

Influence of band gap of p-type hydrogenated nanocrystalline silicon layer on the short-circuit current density in thin-film silicon solar cells

The impact of the optical band gap (E_g) of a p-type hydrogenated nanocrystalline silicon layer on the short-circuit current density (J_sc) of a thin-film silicon solar cell is assessed. We have found that the J_sc reaches maximum when the E_g reaches optimum. The reason for the J_sc on E_g needs to be clarified. Our results exhibit that maximum J_sc is the balance between dark current and photocurrent. We show here that this dark current results from the density of defects in the p-layer and the barrier at the interface between p-and i-layers. An optimum cell can be designed by optimizing the p-layer via reducing the density of defects in the p-layer and the barrier at the p/i interface. Finally, a 6.6% increase in J_sc was obtained at optimum E_g for n-i-p solar cells.     

Silicide/strained Si1-xGex Schottky-barrierinfrared detectors

By employing a thin silicon sacrificial cap layer for silicide formation, the authors successfully demonstrated Pd₂Si/strained Si_1-xGe_x Schottky-barrier infrared detectors with extended cutoff wavelengths. The sacrificial silicon eliminates the segregation effects and Fermi level pinning which occur if the metal reacts directly with Si_1-x Ge_x alloy. The Schottky barrier height of the silicide/strained Si_1-xGe_x detector decreases with increasing Ge fraction, allowing for tuning of the detector's cutoff wavelength. The cutoff wavelength was extended beyond 8 μm in PtSi/Si _0.85Ge_0.15 detectors. It is shown that high quantum efficiency and near-ideal dark current can be obtained from these detectors     

InAlSb红外光电二极管性能研究

在InSb衬底上利用分子束外延生长了p-i-n结构的InAlSb/InSb材料,通过在吸收层和接触层之间生长宽禁带的InAlSb势垒层,验证了势垒层对耗尽层中暗电流的抑制作用。分别基于外延生长的InAlSb材料和InSb体材料,借助标准工艺制备出二极管,并对其电性能进行测量分析,研究发现:77 K温度时,在-0.1 V的外偏电压下,p+-p+-n--n+结构和p+-n--n+结构InAlSb器件的反偏电流分别为3.410-6 Acm-2和7.810-6 Acm-2。基于p+-p+-n--n+结构研制的InAlSb二极管的暗电流保持在一个很低的水平,这为提高红外探测器的工作温度提供了重要基础。