【作者】 刘昕；

【导师】 刘彩池；

【作者基本信息】 河北工业大学 ， 材料物理与化学， 2009， 硕士

【摘要】 GaN是一种宽禁带直接带隙半导体材料,在电子器件领域有着广泛的应用。但由于缺乏合适的衬底材料,限制了器件性能的进一步提高。因此,如何提高GaN外延层的性能就成为GaN材料研究和应用中的主要问题。本文采用金属有机化学气相沉积(MOCVD)生长技术,在蓝宝石衬底上生长出GaN外延层,并进行快速热处理和常规热处理,研究了热处理对GaN外延层的性能的影响。结果表明,经过热处理的样品其晶体质量明显优于未经过热处理的样品,随着快速热处理退火温度的升高,GaN外延层的FWHM逐渐变窄,其晶体质量逐渐变高;随着常规热处理退火时间的延长,GaN外延层的晶体质量有所提高。与未经过热处理的GaN薄膜相比,经过热处理的样品中的残余应力得到了很大缓解。未经过热处理的样品黄光输出强度明显高于经过热处理的样品,表明采用热处理方法提高了GaN薄膜的发光性能。对样品快速热处理前后的电学性能进行了研究,结果显示经过快速热处理的样品其电学性能得到了很大的提高,当样品经过950℃快速热处理后,其载流子浓度达到1×1018cm-3。更多还原

【Abstract】 GaN is wide band gap and direct-gap semiconductor material. It is broadly applied in the area of semiconductor devices. However, the develepment of GaN based devices is confined by the less of suitable substrate materials. So how to improve the quality of GaN epilayers is the important.In this paper, GaN epilayer was grown on sapphire substrate in Metal Organic Chemical Vapor Deposition (MOCVD) reactor. Rapid thermal processor and conventional heat treatment were introduced to study the effect of heat treatment on the properties of GaN epilayers.The results showed that the quality of the GaN epilayer was improved after heat treatment. The full-width at half- maximum (FWHM) of the GaN epilayer became narrow and the quality of the epilayer was improved along with the rise of annealed temperature and annealed time extended. The residual strain of the GaN epilayer heat-treated was released. The yellow-band intensity of the GaN epilayer without heat treatment is higher than that heat-treated. It shows the luminescence property was improved through heat treatment. The electrical performance of the GaN epilayer with heat treatment were compared with the GaN layer without heat-treated, the results showed that the electrical performance was improved after heat treatment. The carrier concentration of the sample which was rapid thermal processor by 950℃is 1×1018cm-3.更多还原