SBIR Phase I: Hybrid Precursor HVPE Growth of AlGaN

这个小型企业创新研究第一阶段项目计划开发一种新的外延生长工艺，用于生产基于III-氮化物材料的长寿命(寿命20,000小时)、高效率(壁塞效率10%)的深紫外光发光二极管(DUV LED)。由于缺乏本土衬底，DUV LED是由异质外延AlInGaN或生长在蓝宝石衬底上的AlGaN薄膜制成的，存在高密度的晶体缺陷。大量的生长缺陷降低了DUV LED的效率、可靠性和寿命。以往的经验表明，由于缺陷的湮灭和应变松弛，厚膜中的晶体缺陷可以减少。这项研究的目标是开发一种新的工艺，以促进厚的III-氮化物材料的生长，从而允许材料松弛和缺陷消失。通过使用不具有强烈气相反应的稳定前驱体，而不是金属有机前驱体，将实现高生长速率。PI还建议修改已与金属有机气体一起使用的混合前体气相外延(HPVPE)淋浴喷头和气体输送系统。将对生长的材料和制造的LED进行表征和评估，以优化拟议的工艺。该提议的技术前景是光明的，因为厚层的生长预计会导致位错的湮灭。拟议的活动将促进对高质量材料和器件生长的了解和理解，这些材料和器件通常很难生长。这方面的工作预计将使LED以外的技术受益。

This Small Business Innovation Research Phase I Project proposes to develop a new epitaxial growth process for production of long-lasting (lifetime 20,000 hours), high-efficiency (wall-plug efficiency 10%) deep ultraviolet light emitting diodes (DUV LEDs) based on III-Nitride materials. Due to the lack of native substrates DUV LEDs are made from heteroepitaxial AlInGaN or AlGaN films grown on sapphire substrates and suffer from a high density of crystal defects. Large concentration of growth defects reduces DUV LEDs' efficiency, reliability and lifetime. Previous experience reveals that crystal defects can be reduced in thick films due to defects annihilation and strain-relaxation. The goal of the research is the development of a new process to facilitate the growth of thick III-Nitride materials and as a consequence allow for material relaxation and defects annihilation. The high growth rate will be achieved by using stable precursors that do not have strong gaseous phase reaction, as opposed to metal organic precursors. The PI proposes also to modify the Hybrid Precursor Vapor Phase Epitaxy (HPVPE) shower head and gas delivery system that has been used with the metal organic gases. The grown materials and the LEDs built will be characterized and evaluated to optimize the proposed process. The technical prospects of the proposal are promising, since growth of thick layers is expected to result in the annihilation of dislocations. The proposed activity will advance the knowledge and understanding of the growth of high quality materials and devices, which are normally difficult to grow. This aspect of the work is expected to benefit technologies other than LEDs.