离子注入重掺杂硅的能级调控及近红外探测器应用研究

发布时间：2018-04-08 23:13

本文选题：离子注入　切入点：飞秒激光　出处：《电子科技大学》2017年硕士论文

【摘要】：受限于单晶硅的禁带宽度,传统的硅基探测器不能满足近红外波段的探测需求,近年来,国内外学者进行了大量的研究和尝试来提高硅基器件的性能。1998年,在SF6气氛下采用飞秒激光辐照法制备的硫族元素超掺杂硅在可见-近红外波段的光吸收率高达90%,这一材料的出现受到了广泛关注和深入研究,目前该材料可用于硅基器件的制备来提高器件的性能,如太阳能电池、光电探测器等。在高能脉冲激光辐照下,单晶硅表面会发生快速融化和再凝固,利用SF6气氛掺杂在高能量情况下超过了硫元素在硅中的固溶度。掺杂的硫元素在硅的禁带中引入了杂质能带,相当于变相使禁带变窄,从而使材料可以吸收近红外波段的光。此外,激光烧蚀使得硅表面重构并产生了一系列的尖锥阵列,样品表面尖锥高度为微米数量级,当光辐照到材料表面,会在尖锥中多次反射,使得材料对可见光的吸收也有显著的提高。虽然在SF6气氛下采用飞秒激光制备的重掺杂硅在可见-近红外波段有很高的吸收,但是由于表面尖锥阵列高度较高,对器件制备造成了一定的障碍。离子注入辅以飞秒激光的工艺很好地解决了这个问题,先通过离子注入将硫元素掺杂到单晶硅表面,再使用较低的脉冲能量和脉冲数目的激光扫描硅片,在激活杂质电学特性的同时,使得硅材料表面尖锥在数微米甚至纳米量级。用该方法制备的重掺杂硅材料对可见光的吸收率仍有90%,对近红外波段的光的吸收率则下降到60%,但仍大幅度高于普通单晶硅。通过对比不同离子注入浓度下制备的重掺杂硅在可见-近红外波段的吸收率,分析材料的吸收率和掺杂浓度的关系。通过霍尔测试表征材料的电学性能,掺杂浓度最高时,载流子面密度接近1015cm-2,但载流子迁移率则随掺杂浓度升高而降低到77cm2v-1s-1,这主要是由超高的掺杂浓度所引起。将重掺杂硅材料制成N+/P光电二极管,测试器件的伏安特性曲线和光电响应。分析不同离子注入剂量对探测器响应度的影响,掺杂剂量低的材料虽然吸收率相对较低,但由于较高的载流子迁移率,在可见-近红外波段仍拥有更高的响应度。飞秒激光结合离子注入的工艺提供了一种制备低成本、宽光谱响应近红外硅基探测器的方法,利用该方法制备的新型光电探测器件的优异性能使其在硅基近红外光电探测器领域有着巨大的应用潜力。
[Abstract]:The band gap is limited to single crystal silicon, silicon photodetector tradition can not meet the need of the detection, near infrared band in recent years, domestic and foreign scholars have conducted research and try a lot to improve the performance of silicon.1998, using sulfur prepared by femtosecond laser irradiation in SF6 atmosphere in the visible and ultra doped silicon infrared light absorption rate as high as 90%, this material has attracted extensive attention and in-depth research, the material can be used for the preparation of silicon based devices to improve the performance of the device, such as a solar battery, photoelectric detector etc. in high-energy pulsed laser irradiation, the silicon surface will happen quickly melted and re in the case of solidification, high energy exceeds the solid solubility of elemental sulfur in silicon by SF6 doping. The sulfur doped atmosphere in the silicon band gap introduced impurity band, which is equivalent to disguise so that the band gap narrowing. The material can absorb infrared light. In addition, the laser ablation of silicon surface reconstruction and array produced a series of sample surface, tip height reaches a micrometer level when light irradiation to the material surface, will be reflected many times in the cone, the material of the absorption of visible light is also significantly improved. Although the use of heavily doped silicon fabricated by femtosecond laser pulses in SF6 atmosphere with high absorption in the visible and near-infrared bands, but due to the surface array high for device fabrication caused some obstacles. By femtosecond laser technology is a good solution to this problem by ion implantation, ion implantation of sulfur doping to the silicon surface, laser scanning wafer using low pulse energy and pulse number, the impurities on the electrical characteristics of activated at the same time, the tip of silicon surface in several micron or even nanometer. Heavily doped silicon material prepared by using the method of visible light absorption rate is 90%, the absorption rate of infrared light is decreased to 60%, but still significantly higher than ordinary monocrystalline silicon. Heavily doped silicon concentration prepared in the visible and near infrared absorption rate by comparing different ion implantation the relationship between absorption rate, analysis of materials and doping concentration. Through the measurements of the electrical properties of materials characterization of Holzer, the highest doping concentration, the carrier density is close to 1015cm-2, but the carrier mobility increases with doping concentration was increased to 77cm2v-1s-1, which is mainly caused by the high doping concentration of heavily doped silicon material. N+/P photodiode, volt ampere characteristic curve and photoelectric test device. Response analysis of different ion implantation dose effect on the sensitivity of the detector, doping dose low material while the absorption rate is relatively low, but due to the high The carrier mobility in the visible and near-infrared bands still have higher responsivity. Femtosecond laser technology combined with ion implantation for preparing low cost provides a method of near infrared silicon detector with wide spectral response, excellent photoelectric model prepared by the method of the detection device can be a the huge potential of application in the field of silicon based near infrared photodetector.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN215

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