A pathway to controllable n-type doping in AlGaN alloys for high power devices

摘要：宽带隙合金AlGaN在大功率应用中的电导控制本研究将通过新的掺杂和缺陷控制工艺，使宽禁带半导体的应用范围超越传统的限制。这将导致有效控制传统上被归类为绝缘体的材料的导电性。扩展目前的掺杂限制扩展了这类材料的功能，以实现否则不可能实现的应用。这项研究将为电力电子提供一种变革性和颠覆性的技术，也将为高效掺杂实现高效的深紫外光净水发射体提供突破性技术。这种颠覆性技术的成功展示将彻底改变美国境内电动马达驱动和其他电力密集型应用中的能量开关和传输、能量存储以及相关应用。因此，白宫已经认识到有必要建立美国？S在这项技术方面的领导地位，作为制造业创新研究所的一部分。总体而言，这项研究将直接导致材料将用于处理自然资源的保护和扩展的应用：(1)允许有效地使用和传输电能，(2)通过使用紫外线消毒获得清洁的饮用水，以及(3)检测污染物和其他流出物。这个项目将提供一个机会，让博士生在本科生的支持下学习宽带隙材料的生长和表征，同时参与S国际合作者网络。这项计划的最终技术目标是展示整个成分范围内AlGaN中可控的N掺杂，并展示一种将超过竞争对手的SiC基器件性能的AlGaN基功率肖特基二极管。需要解决以下挑战：(1)建立掺杂和溶解极限以及Si和Ge；&amp；#8232的激活能；(2)识别AlGaN：Si/Ge中的补偿缺陷和杂质；(3)使用过饱和和新的费米能级点缺陷控制方案来控制所识别的补偿器；(4)展示AlGaN中可控的低、中、高自由电子密度；(5)制作功率肖特基二极管。基于在自然衬底上生长AlGaN薄膜的最新进展，以及关于GaN的Ge掺杂的最新结果，这些挑战最终可以被解决。NCSU的宽带隙实验室一直走在这些发展的前列，不仅展示了点缺陷控制方案，还展示了它的能力，例如第一个演示了具有可观察腔模的深紫外光激光器。所有这些成就都是利用国立大学最先进的金属有机化学气相沉积设备实现的。识别补偿缺陷和杂质将有助于更好地理解AlGaN中的缺陷复合体和宽禁带材料中的缺陷形成。由于建议的费米液位控制方案独立于III-氮化物，先进的点液位控制的演示将促进其在其他材料系统中的应用。

Abstract: Control of the electrical conductivity of the wide bandgap alloy AlGaN for high power applicationsThe proposed research will extend the applicability of wide bandgap semiconductors beyond the traditional limits by novel doping and defect control processes. This will lead to effective control of electrical conductivity
in materials that were traditionally classified as insulators. Extending the current limits of doping extends the functionality of this class of materials to realize applications that otherwise would not be possible.. This research will provide for a transformative and disruptive technology for power electronics and also provide a breakthrough technology for efficient doping to realize efficient deep UV emitters for water purification. The successful demonstration of such disruptive technology would revolutionize energy switching and transmission, energy storage, and related applications in electrical motor drives and other power intensive applications within the US. As such, the White House has recognized the need to build America?s leadership in this technology as part of the manufacturing innovation institutes. In general, this research will directly lead to materials that will be used for applications that deal with the preservation and extension of natural resources by: (1) allowing for the efficient
use and transmission of electrical energy, (2) availability of clean potable water through
disinfection by the use of UV, and (3) the detection of pollutants and other effluents. This
program will provide the opportunity to educate a Ph.D. student with support from an undergraduate student on the growth and characterization of wide bandgap materials while participating with the group?s international collaborators network.The ultimate technical goal of this proposal is to demonstrate controllable n-doping in AlGaN over the whole compositional range and to demonstrate an AlGaN-based power Schottky diode that will exceed the performance of competing SiC-based devices. The following challenges need to be met: (1) establishment of dopant incorporation and solubility limits as well as activation energies for Si and Ge;
(2) identification of compensating defects and impurities in AlGaN:Si/Ge; (3) control of the identified compensators using a supersaturation and a novel Fermi level point defect control scheme; (4) demonstration of controllable low, intermediate, and high free electron densities in AlGaN; (5) fabrication of a power Schottky diode. These challenges can be finally met based on recent advanced in AlGaN thin film growth on native substrates as well as recent results on Ge-doping of GaN. The WideBandgap Laboratory at NCSU has been in the forefront of these developments by demonstrating not only the point defect control schemes but also by demonstrating its capabilities such as the first demonstration
of a deep-UV laser with observable cavity modes. All these achievements have been realized using the state-of-the-art metalorganic chemical vapor deposition facility at NCSU. Identification of compensating defects and impurities will
lead to better understanding of defect complexes in AlGaN and defect formation in wide bandgap materials. Since the proposed Fermi level control scheme is independent of III-nitrides, 
the demonstration of advanced point level control will promote its application in other material systems.