Comparison of plasma-enhanced atomic layer deposition AlN films prepared with different plasma sources

Abstract

A comparative study of thin aluminum nitride (AlN) films deposited by plasma-enhanced atomic layer deposition in the SENTECH SI ALD LL system applying either a direct inductively coupled plasma (ICP) or an indirect capacitively coupled plasma (CCP) source is presented. The films prepared with the ICP source (based on a planar triple spiral antenna) exhibit improved properties concerning the growth rate per cycle, total cycle duration, homogeneity, refractive index, fixed and mobile electrical charges, and residual oxygen content compared to the CCP source, where the comparison is based on the applied plasma power of 200 W. The increase of the plasma power to 600 W in the ICP process significantly reduces the residual oxygen content and enhances the electrical breakdown field. The AlN layers grown under these conditions, with a growth rate per cycle of 1.54 Å/cycle, contain residual oxygen and carbon concentrations of about 10% and 4%, respectively, and possess a refractive index of 2.07 (at 632.8 nm).

Improvement of AlN Film Quality Using Plasma Enhanced Atomic Layer Deposition with Substrate Biasing

“…Numerous parameters have been already investigated such as the type of ALD (thermal versus plasma), 10,11 growth temperature, 12 plasma duration, 12 plasma chemistry, 13−18 and plasma sources. 19 PEALD is often used via a unique plasma source (for instance inductive or capacitive), which generates the ions and radicals necessary for the film growth. Since this date, only a few groups have investigated the effect of substrate biasing during the plasma via an additional power supply.…”

“…AlN growth using PEALD has been widely reported. Numerous parameters have been already investigated such as the type of ALD (thermal versus plasma), , growth temperature, plasma duration, plasma chemistry, − and plasma sources …”