Atomic-scale investigation and its device application for GaN crystal growth

GaN晶体生长的原子尺度研究及其器件应用

基本信息

批准号：
11355002
负责人：
SAKURAI Toshio
金额：
$ 22.53万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

In this project, we have studied on the following subjects as listed below; (1) establishing the general principles for the surface energy minimization and surface reconstruction of GaN surface by MBE-STM (2) understanding the atomistic process for the dopant incorporation and defect formation in GaN epitaxial layers. (3) clarifying the effect of dopant incorporation on the surface electronic properties (4) clarifying the atomistic process in dry etching and its application for the device fabrication. Based on those results, atomic interaction, growth dynamics, surface energetics, strain, and surface/film electronic properties, etc. which are the fundamental process for device fabrication, have been discussed.We have performed systematic investigations of surface reconstructions on Wurtzite GaN(0001) by MBE-STM. Various reconstructions on the GaN(0001) surface are studied and based on the comparison between the STM observations and first-principles total energy calculations, we propose an adatom scheme for the basic 2x2 and 4x4 structures, and others as well. Also, in order to understand atomistic process underlying dry etching processes of Wurtzite GaN, which is of great important for device application, we have carried out STM study of thermally activated dry etching of GaN surface by Cl_2 molecules. Our extensive studies show that at low temperature (〜650C) the dominated etching of Ga-rich GaN(0001) is anti-step-flow etching. On the other hand, at the higher temperature(〜700C), triangular etching pits on terraces start to form. Its single-step depth implies the bilayer-by-bilayer etching.

在这个项目中，我们研究了以下主题，如下所述；（1）建立通过MBE-STM（2）理解GAN外延层中掺杂剂工业和缺陷形成的原子过程的表面能最小化和表面重建的一般原理。（3）阐明掺杂剂工业对表面电子特性的影响（4）阐明了干蚀刻中的原子过程及其在设备制造中的应用。基于这些结果，已经讨论了原子质相互作用，生长动力学，表面能，应变，表面/膜电子性能等，这是设备制造的基本过程。我们已经通过MBE-STM对Wurtzite Gan（0001）的表面重建进行了系统的投资。 GAN（0001）表面的各种重建是研究的，并且基于STM观测值和第一原理总能量计算之间的比较，我们提出了基本2x2和4x4结构的ADATOM方案以及其他结构。同样，为了理解Wurtzite Gan的干蚀刻过程的基础原子过程，这对于设备应用非常重要，我们已经对Cl_2分子对GAN表面进行热激活的干蚀刻进行了STM研究。我们的广泛研究表明，在低温（〜650c）下，富含Ga的GAN（0001）的主导蚀刻是反向流蚀刻。另一方面，在较高的温度（〜700C）下，露台上的三角蚀刻坑开始形成。它的单步深度意味着双层的双层蚀刻。