| Abstract [eng] |
The aim of this work is by using SRIM software packages find optimal ion implantation conditions in order to make thermally stable isolation zones for high electron mobility transistors (HEMTS). In this work was modelled implantation of hydrogen, carbon, aluminum, silicon, gallium and titanium ions into AlGaN/GaN heterostructure. Here is shown differences between vacancy profiles, implanted ions range by using different ion dose, energy and protective masks from photoresist and metals. Using protective 1,4 μm thickness AZ111 (C6H8O) and PMMA (C6H8O) photoresists, the amount of creating vacancies is almost the same (~1,8*10^9 vac. / (cm*ion)), Bragg peak is at 120 nm and 90 nm depth. Using SIEMENS (C51H34O9S2) photoresist there is less created amount of vacancies (7,74*10^8 vac. / (cm*ion)), and Bragg peak is near 100 nm. After performed aluminum ion implantation into AlGaN/GaN heterostructure, it was investigated how the implantation dose and different protective masks affect the wanted isolation areas. The thickness of protective Ni mask doesn’t affect the amount of created vacancies (~3,7*10^9 vac. / (cm*ion)), but has influence to the vacancies formation deapth. Using 10 nm thickness mast Bragg peak reaches 570 nm while using 100 nm of Ni, Bragg peak reaches 380 nm. Tuning the dose of implantation there is no significant difference do one use protective Ti/Al/Ni 30/90/20 nm layer or pure Ni 140 nm protective mask. The implantation of 700 keV aluminum ions showed that photoresist mask, thicker than 3 μm successfully protects target and the 10^13 cm-2 aluminum dose is enough to create high resistivity (over 10^9 Ω) isolation areas. |
