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

摘要：大功率应用中宽禁带AlGaN合金电导率的控制通过新的掺杂和缺陷控制工艺，该研究将使宽禁带半导体的适用性超出传统的限制。这将导致对传统上被归类为绝缘体的材料中的电导率#8232;的有效控制。扩展掺杂的电流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变革性和颠覆性的技术，并为有效掺杂提供突破性技术，以实现用于水净化的高效深紫外发射器。这种颠覆性技术的成功演示将彻底改变美国的能源转换和传输，能源存储以及电动机驱动和其他电力密集型应用的相关应用。因此，白宫已经认识到建设美国的必要性？作为制造业创新研究所的一部分，一般来说，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程序：（1）允许有效的#8232;使用和传输电能，（2）通过#8232;使用紫外线消毒的清洁饮用水的可用性，以及（3）污染物和其他流出物的检测。这个#8232;计划将提供教育博士的机会。学生与本科生的支持下，对宽带隙材料的增长和表征，而参与该集团？的国际合作者网络。该提案的最终技术目标是在整个组成范围内展示AlGaN中的可控n掺杂，并展示一种基于AlGaN的功率肖特基二极管，其性能将超过竞争对手的基于SiC的器件。需要满足以下挑战：（1）建立掺杂剂掺入和溶解度极限以及Si和Ge的活化能;
（2）AlGaN：Si/Ge中补偿缺陷和杂质的识别;（3）使用过饱和和新颖的费米能级点缺陷控制方案控制识别的补偿器;（4）AlGaN中可控的低、中和高自由电子密度的演示;（5）功率肖特基二极管的制造。这些挑战可以最终满足基于最近的先进的AlGaN薄膜生长在原生衬底上，以及最近的结果对Ge掺杂的GaN。NCSU的宽带隙实验室一直处于这些发展的最前沿，不仅展示了点缺陷控制方案，而且还展示了其能力，例如首次展示了具有可观察腔模式的深紫外激光器。所有这些成就都是使用NCSU最先进的金属有机化学气相沉积设备实现的。补偿缺陷和杂质的识别将导致更好地理解AlGaN中的缺陷复合物和宽带隙材料中的缺陷形成。由于所提出的费米能级控制方案与III族氮化物无关，因此先进的点能级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.