Jarosław Tarenko
supervisor: Kamil Kosiel
The main goal of the proposed doctoral dissertation is to develop methods of gallium nitride surface structuring for fabrication of vertical power devices . The scientific aim of the dissertation is to answer the question to what extent and how it is possible to control the structure of gallium nitride surface regarding to two main technological issues - the fabrication of the trench area in vertical MOSFETs and the fabrication of beveled mesa structures in p-i-n diodes and examining and explaining the influence of the structuring processes parameters on the electrical parameters of the final devices.
In first two-semesters of my doctoral studies, I was working on developement of photoresists mask with desired shape and profile (bevel angle) and later on the pattern transfer to the gallium nitride surface by dry etching using inductively coupled plasma reactive ion etching. The influence of the various photoresists as well as reflow process parameters was studied. Finaly, preliminary GaN etching proceses were performed to reproduce the desired shape and slope angle of the photoresist mask. An example of vertical GaN p-i-n diodes fabricated through developed process was also presented.
This work was partially supported by The National Centre for Research and Development under Agreement nr TECHMATSTRATEG-III/0003/2019 for project "Complete vertically integrated technological chain for vertical GaN-on-GaN power electronics: from GaN substrate to Intelligent Energy Bank".