Atomic Layer Deposition of TiN Thin Films by Alternate Supply of Tetrakis (ethymethylamino)-Titanium and Ammonia

Abstract

Atomic layer deposition (ALD) of amorphous TiN films on SrO, between 170°C and 210°C has been investigated by alternate supply of reactant sources, Ti[N(CzHsCH3)z]4 [tetrakis(ethylmethylamino)titanium:TEMAT] and NH3. Reactant sources were injected into the reactor in the following order:TEMAT vapor pulse, Ar gas pulse, NH3 gas pulse and Ar gas pulse.

Film thickness per cycle was saturated at around 1.6 monolayers (ML) per cycle with sufficient pulse times of reactant sources

at 200 oe. The results suggest that film thickness per cycle could exceed 1ML/cycle in ALD, and are explained by the chemisorption

mechanism of the reactant sources. An ideal linear relationship between number of cycles and film thickness is confirmed. As a result of surface limited reactions of ALD, step coverage was excellent. Particles caused by the gas phase reactions between TEMAT and NH3 were almost absent because TEMAT was segregated from NH3 by the Ar pulse. In spite

of relatively low substrate temperature, carbon impurity was incorporated below 4 atom %.