Refined isolation techniques for GaN-based high electron mobility transistors

This work investigates the Ar+/N+ based ion implantation and Ar based reactive ion etching (RIE) techniques for device isolation. A comparison of ion implantation technique with three ion energies (20/35/65 keV) and 4 energies (20/35/65/160 keV) of Ar+ and N+ with different ion doses for isolation was reported. Use of 4 energy ion implantation provided better isolation. Ar based single and dual step reactive ion etching process was also explored for the mesa isolation of GaN HEMTs. The etch rate increases (44.7%) significantly after mixing of Ar gas directly with BCl3: Cl2 combination. Hence, the Ar addition in the single step etching proved to be more beneficial as compared to the double step etching technique.