Interplay between C-doping, threading dislocations, breakdown, and leakage in GaN on Si HEMT structures
Interplay between C-doping, threading dislocations, breakdown, and leakage in GaN on Si HEMT structures
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DOI：
10.1063/1.5141905
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发表时间：
2020-04-01
期刊：
影响因子：
1.6
通讯作者：
Erlbacher, T.
中科院分区：
文献类型：
--
作者：
Besendoerfer, S.;Meissner, E.;Erlbacher, T.
这项工作描述了高电子迁移率晶体管结构与C掺杂GaN电流阻挡层的电特性和材料特性的相关性，通过具有不同掺杂水平的非本征或自掺杂工艺生长。对于所有样品，观察到对于增加的C掺杂水平的螺纹位错密度方面的晶体质量的增加的退化。用于自掺杂样品的不同生长条件对整体降解没有作用，但观察到更高比例的螺纹螺旋位错。与掺杂过程无关，所有TSD中有90%被发现充当穿过AlGaN势垒的强漏电流路径。这是统计发现，并直接验证了导电原子力显微镜直接相关的缺陷选择性蚀刻。观察到垂直击穿随着C-浓度的增加而增加，并且在C-浓度高于约10（19）cm（-3）时达到饱和。这归因于自由电荷载流子的补偿增加，直到发生自补偿。TDs对高C浓度的渐进影响也可能发挥作用，但无法明确揭示我们的材料。
This work describes electrical characteristics and the correlation to material properties of high electron mobility transistor structures with a C-doped GaN current blocking layer, grown either by an extrinsic or auto-doping process with different doping levels. Increasing degradation of crystalline quality in terms of threading dislocation density for increasing C-doping levels was observed for all samples. Different growth conditions used for the auto-doped samples played no role for overall degradation, but a higher fraction of threading screw dislocations was observed. Independent of the doping process, 90% of all TSDs were noted to act as strong leakage current paths through the AlGaN barrier. This was found statistically and was directly verified by conductive atomic force microscopy in direct correlation with defect selective etching. Vertical breakdown was observed to increase with increasing C-concentration and saturated for C-concentrations above around 10(19) cm(-3). This was attributed to an increasing compensation of free charge carriers until self-compensation takes place. A progressive influence of TDs for high C-concentrations might also play a role but could not be explicitly revealed for our material.