Jarosław Tarenko
supervisor: Kamil Kosiel
The main task of the proposed doctoral dissertation is to develop methods of GaN surface structuring for fabrication of vertical power devices . The scientific aim is to answer the question to what extent and how it is possible to control the structure of GaN surface regarding to two main technological issues - the fabrication of the trench area in vertical MOSFETs and the fabrication of bevelled mesa structures in p-i-n diodes and examining the influence of the structuring processes parameters on the electrical parameters of the final devices.
Till now I was working on development of photoresists mask with desired shape and profile (bevel angle) and later on the pattern transfer to the GaN surface by dry etching using inductively coupled plasma reactive ion etching. With optimization of reflow process parameters the different angles of bevelled mask were obtained. Subsequently I examine the effect of various BCl3 ICP/RIE plasma parameters (RIE and ICP power) on the etching of bevelled mesa structures . The selectivity of etching of GaN over photoresists mask was close to 1:1 allows to exact transfer of the pattern from the mask to the semiconductor structure with low bevel angle.
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".