High-temperature atomic layer deposition of silicon oxide films using Tris (dimethylamino)silane and ozone

Atomic layer deposition (ALD) benefits from high process temperatures when the substrate is not temperature- sensitive because the films deposited at higher temperatures exhibit better electrical properties. In this study, we investigated the ALD process of silicon oxide films by alternating injections of tris(dimethylamino)silane (trisDMAS) and O3/O2 3 /O 2 at temperatures ranging from 400 to 700 degrees C. The saturation dose of tris-DMAS was 1.5 x 106 6 L at 400 degrees C. Self-limiting growth with a growth rate of approximately 0.9 angstrom/cycle was observed up to 600 degrees C, allowing excellent step coverage. However, at 700 degrees C, the growth rate increased significantly to 4.6 angstrom/cycle, carbon and nitrogen impurities were detected by secondary ion mass spectrometry, and step coverage was poor, supporting the thermal decomposition of tris-DMAS at this temperature. Therefore, the optimum temperature for ALD SiO2 2 using tris-DMAS is 600 degrees C for application as an insulating film on high aspect ratio patterns. At this temperature, the leakage current density was 0.58 nA/cm2, 2 , and the oxide-trapped charge density was 4.0 x 1010 10 cm-2 .