Licata Olivia G, Mazumder Baishakhi
Department of Materials Design and Innovation, University at Buffalo, Buffalo, NY14260, USA.
Microsc Microanal. 2022 Mar 15:1-9. doi: 10.1017/S1431927622000460.
The occurrence of multi-hit events and the separation distance between multi-hit ion pairs field evaporated from III-nitride semiconductors can potentially provide insights on neighboring chemistry, crystal structure, and field conditions. In this work, we quantify the range of variation in major III-N and III-III ion-pair separation to establish correlations with bulk composition, growth method, and ion-pair chemistry. The analysis of ion-pair separation along the AlGaN/GaN heterostructure system allows for comparison of Ga-N and Ga-Ga ion-pair separation between events evaporated from pure GaN and Al0.3Ga0.7N. From this, we aim to define a relative measure for the bond length of ion pairs within an AlGaN/GaN heterostructure. The distributions of pair separation revealed a distinct bimodal behavior that is unique to Al-N2+ ion pairs, suggesting the occurrence of both co-evaporation and molecular dissociation. Finally, we demonstrated that the two modes of ion-pair events align with the known variation in the surface electric field of the AlGaN(0001) structure. These findings demonstrate the utility of atom probe tomography in studying the crystallographic nature of nitride semiconductors.
从III族氮化物半导体中发生的多次撞击事件以及场蒸发的多次撞击离子对之间的分离距离，有可能为相邻化学、晶体结构和场条件提供见解。在这项工作中，我们量化了主要III-N和III-III离子对分离的变化范围，以建立与体相组成、生长方法和离子对化学的相关性。沿着AlGaN/GaN异质结构系统对离子对分离的分析，使得我们能够比较从纯GaN和Al0.3Ga0.7N蒸发的事件之间的Ga-N和Ga-Ga离子对分离。据此，我们旨在定义AlGaN/GaN异质结构内离子对键长的相对度量。对离子对分离的分布揭示了Al-N2+离子对特有的明显双峰行为，表明同时发生了共蒸发和分子解离。最后，我们证明了离子对事件的两种模式与AlGaN(0001)结构表面电场的已知变化一致。这些发现证明了原子探针断层扫描在研究氮化物半导体晶体学性质方面的实用性。
