Investigations on HVPE of non-and semipolar GaN

非和半极性GaN的HVPE研究

• 批准号: 72517506
• 负责人: Professor Dr. Ferdinand Scholz
• 金额: --
• 依托单位: Institut für Funktionelle Nanosysteme
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/72517506?language=en
• 关键词: Investigations; HVPE; non; semipolar; GaN

As a part of the research group proposal "Polarization field control in nitride light emitters", the current project aims to investigate the epitaxial growth of high quality thick non- and semipolar GaN layers which then can be used as substrates for a subsequent heterostructure deposition. To this end, we will combine the high flexibility of metalorganic vapor phase epitaxy (MOVPE) for the optimization and defect reduction in such layers with the high growth rate of hydride vapor phase epitaxy (HVPE) for the growth of several 100μm thick layers. In the first phase of the project, we have developed a method which allows to achieve semipolar planar surfaces by making use of the c-plane growth direction. This is done by etching grooves with c-plane like side walls into sapphire wafers of specific orientations from which the subsequent epitaxial growth starts. In the second phase, we will optimize this method in particular for the (10_11) plane of GaN grown on (11_23) (n-plane) sapphire wafers to realize large area semipolar planes of GaN with low defect density. Additionally, we will investigate whether this procedure is also applicable to other semipolar surfaces like, e.g. the (20_21) surface. Subsequently, these layers will be overgrown by HVPE to achieve several 100μm thick layers, which eventually can be separated from the sapphire substrates to get free-standing semipolar GaN wafers. By using marker layers, a profound understanding of the growth process can be obtained. Besides varying slightly the substrate misorientation for an improved coalescence of the stripes, we will also study approaches to grow such layers directly by HVPE. The close collaboration with the partners of our research group will help to understand the microstructure of such layers and eventually reduce the crystalline defects typically involved in such non-c-plane growth procedures.

作为研究小组提案“氮化物光发射器中的偏振场控制”的一部分，当前项目旨在研究高质量厚非极性和半极性GaN层的外延生长，然后可以用作后续异质结构沉积的衬底。为此，我们将结合联合收割机的高灵活性的金属有机气相外延（MOVPE）的优化和缺陷减少在这样的层与氢化物气相外延（HVPE）的高生长速率的几个100μm厚的层的生长。在该项目的第一阶段，我们已经开发出一种方法，它允许通过利用c-平面生长方向来实现半极性平面表面。这是通过将具有c平面状侧壁的凹槽蚀刻到特定取向的蓝宝石晶片中来完成的，随后的外延生长从该特定取向开始。在第二阶段中，我们将特别针对在（11_23）（n面）蓝宝石晶片上生长的GaN的（10_11）面优化该方法，以实现具有低缺陷密度的GaN的大面积半极性面。此外，我们将研究这个过程是否也适用于其他半极性表面，如（20_21）表面。随后，这些层将被HVPE过度生长，以获得几个100μm厚的层，最终可以将其与蓝宝石衬底分离，以获得独立的半极性GaN晶片。通过使用标记层，可以获得对生长过程的深刻理解。除了稍微改变衬底的取向差以改善条纹的聚结之外，我们还将研究直接通过HVPE生长这种层的方法。与我们研究小组的合作伙伴的密切合作将有助于了解这些层的微观结构，并最终减少这种非c平面生长过程中通常涉及的晶体缺陷。