GOALI/Collaborative Research: Understanding Cracking and Defect Formation During AlN Crystal Growth

CMMI - 0928556 - GOALI/合作研究：了解AlN晶体生长过程中的裂纹和缺陷形成本提案将使用2009年美国复苏和再投资法案（公法111-5）提供的资金进行奖励，并符合2009年3月20日白宫备忘录第2节的要求，题为“确保负责任的复苏法案资金支出”。我还确认，作为认可的项目官员，该提案不支持《复苏法案》A部分第1604条所述的项目。本研究的目的是：1)获得对氮化铝（AlN）单晶在加工过程中裂纹萌生和整体晶体质量演变的理解；2)创建一种预测方法。AlN具有出色的电学和热学性能，使其特别适合于大功率、高频、节能的电子和光子器件，如发光二极管（led）和激光二极管，但AlN的使用目前受到高生产成本的限制。该提案的工业合作伙伴Crystal IS已经开发出一种新技术，用于种植直径达50毫米的大型AlN晶体。然而，当材料从高达2300摄氏度的生长温度冷却下来时，这些大晶体往往会由于应力而破裂。在这个项目中，来自康奈尔大学和伦斯勒大学的应力测量和加载材料模拟领域的专家团队将研究AlN作为一种“结构”材料。高能x射线将被用来“观察”装载在测试样品内部深处的氮化铝晶体结构。通过将模拟结果与实验结果相匹配，将确定与强度、刚度和抗断裂性相关的关键温度相关的机械性能。该信息将用于晶体生长过程模型，以预测给定生长条件下的晶体质量。这项工作将指导晶体生长过程设计师，以便生产出大而高质量的晶体。这项工作将被纳入参与机构的教育计划。产业合作将提供极好的学习机会。开发的任何实验能力都将驻留在x射线光束线上，并可供其他用户使用。

CMMI - 0928556 - GOALI/Collaborative Research: Understanding Cracking and Defect Formation During AlN Crystal Growth This proposal will be awarded using funds made available by the American Recovery and Reinvestment Act of 2009 (Public Law 111-5), and meets the requirements established in Section 2 of the White House Memorandum entitled, Ensuring Responsible Spending of Recovery Act Funds, dated March 20, 2009. I also affirm, as the cognizant Program Officer, that the proposal does not support projects described in Section 1604 of Division A of the Recovery Act.The objectives of this research are to i) gain an understanding of and ii) create a predictive methodology for crack initiation and overall crystal quality evolution for Aluminum Nitride (AlN) single crystals during processing. AlN has outstanding electrical and thermal properties making it particularly well-suited for high power, high frequency, energy efficient electronic and photonic devices, such as light emitting diodes (LEDs) and laser diodes, but the use of AlN is currently limited by the high production cost. Crystal IS, the industrial partner on this proposal, has developed a new technology for growing large AlN crystals - up to 50 mm in diameter. However, these large crystals often crack due to stresses that arise when the material is cooled from its growth temperature as high as 2300C. In this project, a team of experts in the fields of stress measurement and simulation of loaded materials from Cornell and Rensselaer will study AlN as a "structural" material. High energy X-rays will be used to "see" the crystal structure of the AlN deep inside a test specimen as it is loaded. By matching simulations to the experimental results, key temperature-dependent mechanical properties, related to strength, stiffness and fracture resistance will be determined. This information will be used in a crystal growth process model to predict crystal quality for given growth conditions.This work will guide crystal growth process designers so that large, high quality crystals can be produced. This work will be integrated into educational programs at the participating institutions. The industrial collaboration will provide excellent learning opportunities. Any experimental capabilities developed will reside at the x-ray beamline and become available to other users.