碳化硅雪崩紫外探测器结构仿真研究

发布时间：2018-04-12 18:02

本文选题：雪崩紫外探测器 + SAM结构　；参考：《西安电子科技大学》2015年硕士论文

【摘要】：紫外探测技术被广泛应用于生化检测、可燃性气体尾焰探测及导弹羽烟探测等紫外辐射探测等领域。由于4H-SiC具有宽带隙的特点,用其制备的紫外光电探测器具有日盲特性。在紫外探测器领域,常规的剂量型紫外探测器已经趋于成熟,目前的难点是如何探测弱紫外以及单光子探测。在弱光探测中,探测器的内部增益十分重要,固体紫外探测器依靠雪崩倍增来实现对弱紫外信号的放大,工作在盖格模式的碳化硅雪崩紫外探测器增益可以达到106,达到与光电倍增管相当的增益水平。碳化硅分离吸收倍增层雪崩紫外探测器具有暗电流低,增益高,工作电压低的优点。本文研究了4H-SiC分离吸收倍增雪崩紫外探测器的工作机理,建立了两种不同吸收倍增层的SAM结构雪崩紫外探测器,通过仿真,研究了两种不同结构的SAM结构雪崩紫外探测器的反偏IV特性,研究n型吸收倍增层结构分离吸收倍增层雪崩紫外探测器在不同偏压下雪崩紫外探测器的光谱响应曲线,分析了不同偏压下的量子效率随波长的变化,仿真研究了器件的瞬态特性。建立了两种斜角台面结构:正斜角台面和负斜角台面结构,在此基础上,仿真分析了正台面和负台面对器件特性的影响。并得出如下结论:n型吸收倍增层要优于p型吸收倍增层。4H-SiC分离吸收倍增紫外探测器具有极低的暗电流和明显的光电流响应;偏置电压对雪崩紫外探测器的响应度影响很大,响应度随偏压一开始线性增加,随后在到达雪崩击穿电压附近,响应度剧增;负台面会在器件边缘形成一个峰值电场,该峰值电场会造成击穿电压的降低,击穿电压随台面角度的减小是先减小后增大的关系;正台面可以降低器件的暗电流,但降低程度有限,不会超过一个量级,并且当台面角度很极端时,暗电流的降低才会明显。此外,本文还给出了斜角台面的实现方法。本文研究了分离吸收倍增层紫外探测器的工作机理,建立了n型吸收倍增层和p型吸收倍增层结构,仿真比较了n型吸收倍增层和p型吸收倍增层的暗电流特性。仿真研究了n型吸收倍增层的光暗电流以及不同偏压下的光谱响应曲线和量子效率曲线和瞬态特性。介绍了正斜角台面和负斜角台面,通过仿真分析研究了正斜角台面结构和负斜角台面对器件暗电流以及击穿电压的影响,给出了斜角台面的实现方法。这为以后雪崩紫外探测器的研制提供理论指导,为器件结构的设计提供借鉴。
[Abstract]:Ultraviolet detection technology is widely used in biochemical detection, combustible gas tail flame detection, missile plume detection and other areas of ultraviolet radiation detection.Because of the wide band gap of 4H-SiC, the UV photodetector prepared by 4H-SiC has the characteristics of solar blindness.In the field of ultraviolet detectors, the conventional dose type ultraviolet detectors have become mature. At present, the difficulty is how to detect weak ultraviolet and single photon detection.In weak light detection, the internal gain of the detector is very important. The solid ultraviolet detector relies on avalanche multiplication to amplify the weak ultraviolet signal.The gain of silicon carbide avalanche UV detector working in Gage mode can reach 106, which is equivalent to the gain level of photomultiplier tube.Silicon carbide separated absorption layer avalanche UV detector has the advantages of low dark current, high gain and low operating voltage.In this paper, the working mechanism of 4H-SiC separation and absorption double avalanche ultraviolet detector is studied. Two kinds of SAM structure ultraviolet detectors with different absorption and multiplication layers are established.The inverse bias IV characteristics of two different structures of SAM structure avalanche UV detectors are studied. The spectral response curves of n-type absorption-multiplicative layer structure separated absorption multiplication layer avalanche ultraviolet detectors under different bias voltages are studied.The variation of quantum efficiency with wavelength at different bias voltages is analyzed and the transient characteristics of the devices are simulated.Two kinds of diagonal Mesa structures, positive and negative, are established. Based on these, the effects of positive and negative countertops on the device characteristics are simulated and analyzed.It is concluded that: n absorption multiplication layer is superior to p type absorption multiplication layer. 4H-SiC separation absorption multiplication ultraviolet detector has very low dark current and obvious photocurrent response, and bias voltage has great influence on the response of avalanche ultraviolet detector.The responsivity increases linearly with the bias voltage, then increases dramatically near the avalanche breakdown voltage, and a peak electric field is formed at the edge of the device, which causes the breakdown voltage to decrease.The breakdown voltage decreases first and then increases with the decrease of the angle of the Mesa, and the reduction of the dark current of the device is limited to a limited extent, which is not more than one order of magnitude, and the decrease of the dark current is obvious when the angle of the Mesa is very extreme.In addition, the realization method of diagonal table is also given in this paper.In this paper, the working mechanism of UV detector with separated absorption and multiplication layer is studied. The structure of n-type absorption multiplication layer and p-type absorption multiplication layer are established, and the dark current characteristics of n-type absorption multiplier layer and p-type absorption multiplication layer are simulated and compared.The spectral response curves, quantum efficiency curves and transient characteristics of n-type absorption and multiplication layers under different bias voltages are studied by simulation.The positive and negative angle table are introduced. The structure of the positive diagonal table and the influence of the negative diagonal table on the device dark current and breakdown voltage are studied by simulation, and the realization method of the oblique angle table is given.This provides theoretical guidance for the future development of avalanche UV detector and provides reference for the design of device structure.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN23

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