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

CMMI - 0928556 - GOALI/协作研究：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提供的资金进行奖励（公法111-5），并符合3月20日名为“确保负责任地支出复苏法案资金”的白宫备忘录第2节规定的要求，2009.我还确认，作为认知项目官员，该提案不支持恢复法案A部分第1604节中描述的项目。本研究的目标是i）了解和ii）创建一个预测方法，用于氮化铝（AlN）单晶在加工过程中的裂纹萌生和整体晶体质量演变。AlN具有出色的电学和热学性能，使其特别适合于高功率、高频、节能的电子和光子器件，例如发光二极管（LED）和激光二极管，但AlN的使用目前受到高生产成本的限制。Crystal IS是该提案的工业合作伙伴，已开发出一种用于生长直径高达50 mm的大型AlN晶体的新技术。然而，这些大晶体经常由于当材料从其高达2300 ℃的生长温度冷却时产生的应力而破裂。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“结构”材料。高能X射线将被用来“看到”AlN的晶体结构深处的一个测试样本，因为它是加载。通过将模拟与实验结果相匹配，将确定与强度、刚度和抗断裂性相关的关键温度依赖性机械性能。这些信息将被用于晶体生长过程模型中，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人员，以便生产出大的高质量晶体。这项工作将纳入参与机构的教育方案。工业合作将提供良好的学习机会。开发的任何实验能力将驻留在X射线束线上，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.