SBIR Phase I: Realization of Transparent Gallium Nitride Wafers by Ammonothermal Growth

SBIR 第一阶段：通过氨热生长实现透明氮化镓晶圆

• 批准号: 1142356
• 负责人: Tadao Hashimoto
• 金额: $ 14.95万
• 依托单位: SixPoint Materials, Inc.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1142356&HistoricalAwards=false
• 关键词: SBIR; Phase; Realization; Transparent; Gallium

This Small Business Innovation Research Phase I project will address the coloration problem of gallium nitride (GaN) grown by the ammonothermal method. Despite its promise to reduce the cost of GaN wafers by 90%, the ammonothermal growth technique has a coloration problem which impedes the use of the resulting substrates for high-brightness light emitting diodes (HB-LEDs). The current major application of GaN wafers is for growing laser diodes (LDs), for which performance is not seriously affected by the coloration issue. However, optical loss in the substrate is a serious issue for HB-LEDs. This project aims to further develop the ammonothermal growth technology to realize low-cost, transparent GaN wafers usable for HB-LEDs. Removing oxygen, which is the primary impurity in ammonothermal bulk GaN, is one of the most challenging aspects of this effort because of the presence of oxygen-sensitive mineralizers. In the Phase I project, we will first conduct controlled sets of experiments to reveal the correlation between impurities and coloration. We will also develop an improved process to minimize the oxygen contamination. The goal of the Phase I project is to prove the feasibility of these new approaches in obtaining transparent GaN.The broader impact/commercial potential of this project is the realization of low-cost, transparent GaN wafers via ammonothermal growth, which will improve the performance and reduce the cost of HB-LEDs. The current high price of GaN wafers does not permit cost competitiveness of HB-LEDs with competing products. The high wafer cost is attributed to the current labor-intensive, low-yield production method of hydride vapor phase epitaxy (HVPE). Since the ammonothermal growth process is a scalable liquid-phase method, it is expected to reduce GaN wafer cost by 90%. The availability of low-cost, transparent GaN wafers will permit substrates grown via this method to address a market which is ten times the size of the current niche (~$1 billion in 2015). Currently, several domestic and international competitors are pursuing this goal; however, none has achieved colorless GaN wafers suitable for the HB-LED application. Our novel processes will directly address the oxidation problem of mineralizers which, we expect, will solve the coloration problem. This project will contribute to realization of low-cost HB-LEDs not only for energy-efficient solid-state lighting products, but also for automobile headlamps and display backlights.

这个小型企业创新研究第一阶段项目将解决氨热法生长的氮化镓(GaN)的着色问题。尽管氨热生长技术承诺将GaN晶片的成本降低90%，但它存在着色问题，阻碍了所产生的衬底用于高亮度发光二极管(HB-LED)。目前GaN晶片的主要应用是生长激光二极管(LD)，其性能不会受到着色问题的严重影响。然而，衬底的光学损耗对HB-LED来说是一个严重的问题。该项目旨在进一步开发氨热生长技术，以实现可用于HB-LED的低成本、透明的GaN晶片。由于氧敏感矿化剂的存在，去除氨热GaN体相中的主要杂质氧是这项工作中最具挑战性的方面之一。在第一阶段项目中，我们将首先进行一系列受控实验，以揭示杂质和着色剂之间的相关性。我们还将开发一种改进的工艺，将氧气污染降至最低。第一阶段项目的目标是证明这些新方法在获得透明GaN方面的可行性。该项目更广泛的影响/商业潜力是通过氨热生长实现低成本、透明的GaN晶片，这将提高HB-LED的性能并降低成本。目前GaN晶片的高价格不允许HB-LED与竞争产品的成本竞争力。晶圆成本高是由于目前氢化物气相外延(HVPE)的劳动密集型、低成品率的生产方法。由于氨热生长工艺是一种可扩展的液相生长方法，因此有望将GaN晶片成本降低90%。低成本、透明的GaN晶片的问世将使通过这种方法生长的衬底能够满足这个市场的需求，这个市场的规模是目前利基市场的十倍(2015年约10亿美元)。目前，国内外几家竞争对手都在追求这一目标，但还没有一家公司实现了适合HB-LED应用的无色GaN晶片。我们的新工艺将直接解决矿化剂的氧化问题，我们预计这将解决着色问题。该项目将有助于实现低成本的HB-LED，不仅用于节能固态照明产品，还用于汽车前照灯和显示背光。