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磁控溅射制备PbTe薄膜及Al惨杂性能的研究
【作者】 卢慧粉；
【导师】 曹文田；
【作者基本信息】 山东师范大学 ， 微电子学与固体电子学， 2012， 硕士
【摘要】 PbTe作为一种重要的Ⅳ-Ⅵ族化合物半导体材料，具有优良的光电和热电特性，如折射率较高和热导率较低，在红外探测、光纤激光技术及温差制冷方面已有广泛的应用。本论文主要从两个方面对PbTe进行了研究：在硅衬底上制备了PbTe薄膜，研究了工艺参数对PbTe薄膜的结晶性能、光学透射率和电学性能的影响；在硅衬底上用磁控溅射的方法制备了Al掺杂PbTe薄膜并把制备的薄膜放入真空退火炉中退火，研究了退火温度和退火时间对薄膜的影响。主要研究成果如下：1.利用磁控溅射法在不同实验条件下制备了PbTe薄膜，研究了溅射功率、衬底温度、薄膜厚度对薄膜的结晶性能、光学性能和电学性能的影响。研究表明：（1）在不同功率下所制备的碲化铅薄膜都具有明显的(200)择优取向性，并且随着溅射功率的增大，薄膜的择优取向逐渐提高，透射率变大，电阻率减小。在功率为30W的条件下制备的薄膜的质量最好。（2）对在实验条件相同的条件下所制备的不同膜厚的碲化铅薄膜进行分析可知，膜厚为200nm的薄膜透射率最高，电阻率最小。（3）不同沉积温度下制备的碲化铅薄膜中，当衬底不加热时薄膜的(200)择优取向性最好。衬底温度为300℃时制备的PbTe薄膜的透射率最高，200℃时制备的薄膜的电阻率最低。2.用磁控溅射的方法制备Al掺杂PbTe薄膜，并对其进行退火处理。研究了退火温度和退火时间对薄膜的影响。研究表明退火温度和退火时间对薄膜的结晶程度、表面形貌、光学性能和电学性能都有重要的影响。（1）在980℃的条件下对样品进行不同时间的退火处理，实验结果说明随着退火时间的延长碲化铅的(200)衍射峰高度越来越低。样品表面上出现的黑色花状聚集越来越密集，排列越来越均匀。样品的透射率和电阻率都随着退火时间的延长呈现出减小的趋势。（2）在不同温度下退火的样品都具有良好的(200)择优取向，随着退火温度的升高PbTe的(200)衍射峰强度下降,半高宽度较窄。退火前样品的表面呈现片状堆砌结构，经过退火处理后，表面出现了花状聚集，并且随着温度的升高花状聚集的数量越来越多，分布越来越均匀。在1173K的条件下退火得到的样品透射率和电阻率都是最大的。
【Abstract】 As a very importantⅣ-Ⅵcompound semiconductor, PbTe has excellent photoelectric andthermoelectric characteristics, such as the high refractive index and the positive temperaturecoefficient of the gap，the large carrier mobility. Those unusual charaeteristies make PbTesemiconductor unique among polar compounds and have important application in many fields,such as infrared detectors, light-emitting devices and more recently as infrared laser in fiberoptics, thermoelectric materials, solar energy panel and window coatings. In this paper, we fromtwo aspects to study PbTe semiconductor material: first, we deposit PbTe films onto Si(111)substrate by magnetron sputtering and sutdy the effect of the process parameters on the PbTefilms of crystallization properties, optical transmission rate and electrical properties; second,Al-doped PbTe films were prepared by radio frequency magnetron sputtering and then annealedin the vacuum resistance furnace, the effect of annealing temperature and annealing time on thecharacteristics of Al/PbTe films were investigated. The main research results are as follows:1. We deposit PbTe films by magnetron sputtering at different experimental conditions and sutdythe effect of the sputtering power, substrate temperature, film thickness on crystallizationproperties, optical transmission rate and electrical properties of PbTe films. Research shows that:(1) PbTe thin films have strong (200) optimizing orientation direction prepared in differentpowers. With the increase of sputtering power, the preferred orientation of films graduallyimprove, transmission rate improve, resistivity reduce. We can obtain the best quality films at30W power condition.(2) From the study of PbTe thin films with different thicknesses prepared at the sameexperimental condition, we can conclued that film with 200nm thickness has the highesttransmission rate and minimum resistivity.(3) Among those PbTe thin films deposited at different deposition temperatures, the filmsprepared at room temperature have strongest (200) optimizing orientation direction. We can getthe highest transmission rate when the substrate temperature is 300℃, while, when the substrate temperature is 200℃, the resistance of PbTe film is the lowest.2. The Al-doped PbTe films were deposited onto Si substrate by radio frequency magnetronsputtering and then annealed in the vacuum resistance furnace. The effect of annealingtemperature and annealing time on the characteristics of Al/PbTe films were investigated.Itindicates that the annealing time and temperature have a great influence on the surfacemorphology, transmittance and resistivity of the Al/PbTe thin films.(1) The Al-doped PbTe thin films were annealed at 980℃conditions for different times, theexperimental result indicates that with the time of annealing extension , the height of PbTe(200)diffraction peak lower. On the surface of the samples flower shape gathers become more andmore intensive and evenly. The transmission rate and resistivity of The samples present a trendof decrease as the extension of annealing time.(2) All the samples annealed at different temperatures have obvious (200)directionoptimizing orientation; after annealed, the height of the diffraction peak (200) markedly reduced,some flower shape gathers appear on the surfaces of the specimens.with the annealingtemperature increases, flower shape gathers become more and more intensive and evenly. Thesample which annealed at 1173 K has the highest transmission rate and largest resistivity.