黑硅材料的制备及器件研究

发布时间：2018-06-27 04:16

本文选题：黑硅 + 光吸收　；参考：《电子科技大学》2015年硕士论文

【摘要】：黑硅是通过一定的处理方法在硅材料表面刻蚀出一定的微结构而形成的。相比于单晶硅,黑硅对可见光到近红外(250nm-2500nm)都具有很高的吸收率,黑硅如此优异的光学性能受到了国内外众多研究人员的关注。本文通过多种刻蚀方法对硅材料进行刻蚀,并且分别对其进行形貌表征和光学特性的测试。制备基于黑硅材料的MSM结构光电探测器件和N+/N型光电器件,并对器件的电学性能进行了研究。分别采用了酸法刻蚀、碱法刻蚀、电化学刻蚀和飞秒激光辐照法对硅片进行了刻蚀,使之表面微观结构发生了一定的变化。酸法刻蚀在黑硅表面形成随机分布大小不一的纳米孔,碱法刻蚀则是在表面出现规则分布大小一致的微米量级正四棱尖锥阵列,电化学腐蚀法是在硅材料表面刻蚀出随机分布大小不一的微米孔,飞秒激光辐照法是在硅片表面形成了不规则分布的微米尖锥。之后分别对样品进行了光学特性的测试,酸法和碱法刻蚀的样品均是对可见光的吸收率有了较大的提高,近红外吸收率仍然较低;电化学腐蚀采用了P型掺杂浓度为1019cm-3的硅材料,最终刻蚀出的黑硅对可见光和近红外光有80%左右的吸收率;飞秒激光脉冲辐照法制备的黑硅对可见光和近红外光均有90%以上的吸收率。通过对单次刻蚀呈现出的微观结构尺寸的分析,尝试在微米结构上制备出纳米结构,从而形成一定的折射率渐变的效果以达到减少反射增加吸收率的目的。采用先碱法刻蚀后酸法刻蚀制备的黑硅材料表面形成了微纳双重结构,对比酸法刻蚀前后的吸收率,发现酸法刻蚀之后有了一定的提高,尤其是近红外有了30%左右的提高;先电化学刻蚀后酸法刻蚀,掺杂浓度为1019cm-3的硅材料二次刻蚀之后整个吸收率达到90%左右;先飞秒激光辐照后酸法刻蚀出的黑硅表面微米结构的尖锥表面布满随机分布的纳米孔,吸收率较单纯飞秒激光刻蚀有了2%的提高。最后采用先电化学刻蚀后酸法刻蚀和先飞秒激光辐照刻蚀后酸法刻蚀这两种方法制备的黑硅材料,在材料表面制备金属电极,并对样品进行了一定温度下的退火处理,最终分别制备成MSM结构光电器件和N+/N型光电器件,之后对器件的光电性能进行了测试,分析对比了器件的I-V特性曲线。
[Abstract]:Black silicon is formed by etching a certain microstructure on the surface of silicon by a certain treatment method. Compared with monocrystalline silicon, black silicon has high absorptivity to visible light and near infrared (250nm-2500nm), and its excellent optical properties have attracted much attention from researchers at home and abroad. In this paper, silicon was etched by various etching methods, and its morphology and optical properties were measured. The structure of MSM photodetectors and N / N optoelectronic devices based on black silicon are fabricated. The electrical properties of the devices are studied. Acid etching, alkali etching, electrochemical etching and femtosecond laser irradiation were used to etch the silicon wafers, which resulted in some changes in the surface microstructure. On the surface of black silicon, acid etching forms nano-pores of different size and random distribution, while alkali etching is the appearance of regular micron order quadrangular pyramid arrays on the surface. Electrochemical etching method is used to etch microholes with different random distribution on the surface of silicon. Femtosecond laser irradiation is an irregularly distributed micron-tip on the surface of silicon wafer. Then the optical properties of the samples were tested. The absorptivity of visible light of the samples etched by acid method and alkali method was greatly improved, and the near infrared absorption rate was still low. The silicon with P type doping concentration of 1019cm-3 was used in the electrochemical corrosion, and the absorptivity of the black silicon was about 80% for visible light and near-infrared light. Black silicon prepared by femtosecond laser pulse irradiation has a absorptivity of more than 90% for both visible and near-infrared light. Based on the analysis of the microstructure size of single etching, we try to fabricate nanostructures on micron structure, thus forming the effect of refractive index gradient to reduce the reflection and increase the absorptivity. The surface of black silicon prepared by alkali etching and acid etching formed micro-nano double structure. Compared with the absorption rate before and after acid etching, it was found that acid etching had a certain improvement, especially about 30% increase in near infrared. Electrochemical etching followed by acid etching, secondary etching of silicon material doped with 1019cm-3, and the whole absorption rate of about 90%. The surface of black silicon with micron structure of black silicon etched by femtosecond laser irradiation was filled with randomly distributed nano-holes. The absorptivity is 2% higher than that of femtosecond laser etching. Finally, the black silicon materials were prepared by electrochemical etching, acid etching and femtosecond laser irradiation etching. Metal electrodes were prepared on the surface of the materials, and the samples were annealed at a certain temperature. Finally, MSM optoelectronic devices and N / N optoelectronic devices are fabricated, and then the photoelectric properties of the devices are tested, and the I-V characteristic curves of the devices are analyzed and compared.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.12

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