(Invited) Deposition of Crystalline AlN on Si and SiC Using Atomic Layer Annealing and Pulsed ALD/CVD

Abstract

The low-temperature (< 400 oC) deposition of polycrystalline AlN films on silicon and silicon carbide is demonstrated by atomic layer annealing (ALA) using tris(dimethylamido) aluminum (TDMAA) and anhydrous N2H4 with an argon plasma treatment utilizing a DC or RF bias to tune the ion energy. ALA is a variant of ALD in which after the N2H4 and TDMAA are dose, a pulse of low energy rare ions ions is employed to induce crystalinity. Using TDMAA and N2H4 + Ar+ or Kr+ high-quality AlN films are deposited with large grain size and low oxygen/carbon contamination which can be used as a templating layer for further high speed AlN film growth via sputtering. The deposition of high quality AlN films deposited by ALA are successfully used as templates for sputtered AlN resulting in a >2x improvement in average grain size when compared to an analogous amorphous template layer. TEM imaging shows a crystalline interface between the AlN and Si(111) which is ideal for heat transfer. For SiC, DC bias is not effective due to the large bandgap so ALA must be performed with RF bias to accelerate the ions. Alternative high temperature (580oC thermal ALD with a CVD component using N2H4 and TDMAA can be employed to grow extremely large grain on SiC which can act as a template or rapid growth of highly crystalline AlN by sputtering.