Structural and electrical characterization of thick GaN layers on Si, GaN, and engineered substrates
Structural and electrical characterization of thick GaN layers on Si, GaN, and engineered substrates
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DOI：
10.1063/1.5049393
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发表时间：
2019-02-28
影响因子：
3.2
通讯作者：
Dayeh, Shadi A.
中科院分区：
文献类型：
--
作者：
Tanaka, Atsunori;Choi, Woojin;Dayeh, Shadi A.
氮化镓(GaN)垂直功率器件和其他大带隙材料的一个主要挑战是高缺陷密度，这会影响性能、可靠性和成品率。缺陷通常在晶格失配和热失配的异质界面上成核。在这里，我们报道了在硅衬底和新上市的QRomis衬底技术T(QST)衬底上进行的厚层GaN的选择性区域生长(SAG)，通过缺陷湮灭，使缺陷密度显著降低到与本征衬底几乎相当的水平。我们对GaN-on-Si、GaN-on-QST和GaN-on-GaN三种不同厚度的GaN层厚度分别为5、10、15和20微米的肖特基势垒二极管进行了参数研究。虽然更厚的层导致了缺陷密度的显著降低和二极管正向电流特性的改善，但GaN-on-QST二极管表现出与GaN-on-GaN二极管几乎相似的特性。由于GaN-on-Si中的缺陷密度与GaN-on-QST衬底中的缺陷密度相当，因此需要进一步改进器件结构和/或SAG生长以获得与之相当的性能。
A major challenge in gallium nitride (GaN) vertical power devices and other large bandgap materials is the high defect density that compromises the performance, reliability, and yield. Defects are typically nucleated at the heterointerface where there are both lattice and thermal mismatches. Here, we report the selective area growth (SAG) of thick GaN on Si and on the newly available Qromis Substrate Technology T (QST) substrates that lead to a significant reduction of the defect densities to a level that is nearly comparable to that on native substrates by defect annihilation. We performed a parametric study of the electrical properties of the SAG GaN layers by fabricating and characterizing Schottky barrier diodes for SAG GaN layer thicknesses of 5, 10, 15, and 20 mu m for GaN-on-Si, GaN-on-QST, and GaN-on-GaN diodes. While thicker layers led to a significant reduction in defect densities and improvement in the diode forward current characteristics, the GaN-on-QST diodes exhibited nearly similar characteristics to the GaN-on-GaN diodes. Further improvement in the device structure and/or SAG growth for GaN-on-Si is needed to achieve a comparable performance as the defect densities in the GaN-on-Si are comparable to that of GaN-on-QST substrates.