Generation of a Pristine Sapphire Surface by Oxidation and Solid State Conversion of a Sputtered Al Coating

通过溅射铝涂层的氧化和固态转化生成原始蓝宝石表面

• 批准号: 0211078
• 负责人: Helen Chan
• 金额: $ 60万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2007-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0211078&HistoricalAwards=false
• 关键词: Generation; Pristine; Sapphire; Surface; Oxidation

This project consists of an in-depth investigation into the mechanisms behind a novel method for generating a pristine sapphire surface. The process is named AGOG, representing the three processing steps: Al thin film deposition on sapphire, Growth of an aluminum Oxide layer, and grain Growth to produce a single crystal surface. Processing conditions at each step in the AGOG process will be varied systematically and correlated to the resulting changes in surface structure. The effect of Al film microstructure and thickness on oxidation behavior will be determined. Sapphire of (0001), (11-20), and (01-12) orientation will be used to identify the effect of interface conditions on the Al to alumina phase transformation. Studies of phase transition behavior will be carried out concurrently with oxidation/heating rate experiments. Once a polycrystalline alumina layer has been created, solid-state conversion processing conditions will be examined. Finally, strategies for eliminating hillock growth during the initial oxidation step will be explored.Sapphire, the single crystal form of alumina, is utilized in many important commercial applications where the quality of the final surface finish is critical. One example is the recent use as a substrate material for high-power blue light emitting diodes (LED's) and laser diodes. These devices are required for a large number of applications including full color electroluminescent displays, and read-write laser sources for high-density information storage on magnetic and optical media. The successful commercial production of blue LED's also offers the potential for bright, white light sources derived from solid state devices. Advantages over conventional incandescent and fluorescent sources include far higher energy efficiency and increased reliability. Sapphire is also widely used for visible and midwave infrared (IR) airborne windows and radomes for guidance systems. Currently, the surfaces of sapphire components are finished by a combination of mechanical and chemical polishing. The final polishing steps are time-consuming, and typically make up a significant fraction of the total cost. The AGOG process is a potentially more cost-effective method for achieving a high quality surface finish in sapphire.

该项目包括对一种新方法生成原始蓝宝石表面的新方法的深入研究。 该过程命名为AGOG，代表三个处理步骤：蓝宝石上的薄膜沉积，氧化铝层的生长以及谷物生长以产生单晶表面。 AGOG过程中每个步骤的处理条件将系统地变化，并与所得的表面结构变化相关。将确定膜微结构和厚度对氧化行为的影响。 （0001），（11-20）和（01-12）方向的蓝宝石将用于识别界面条件对AL对氧化铝相变的影响。相变行为的研究将通过氧化/加热速率实验同时进行。一旦创建了多晶氧化铝层，将检查固态转换处理条件。最后，将探索消除初始氧化步骤中丘陵增长的策略。在许多重要的商业应用中，使用了氧化铝的单晶形式，在许多重要的商业应用中，最终表面饰面的质量至关重要。 一个例子是最近用作高功率蓝光发射二极管（LED）和激光二极管的底物材料。 这些设备是大量应用所需的设备，包括全彩电动发光显示器和用于磁性和光学介质上的高密度信息存储的读取激光源。 Blue LED的成功商业生产还提供了从固态设备衍生出的明亮白光来源的潜力。 优于常规白炽灯和荧光源的优势包括更高的能源效率和提高的可靠性。蓝宝石还广泛用于可见的和中部红外（IR）空中窗户和辐射，用于制导系统。 当前，蓝宝石组件的表面是通过机械和化学抛光的组合完成的。 最终的抛光步骤是耗时的，通常占总成本的很大一部分。 AGOG过程是一种在蓝宝石中获得高质量表面饰面的可能更具成本效益的方法。