Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication

Low temperature silicon dioxide by thermal atomic layer deposition: investigation of material properties

Hiller, D.; Zierold, R.; Bachmann, J.; Alexe, M.; Yang, Y.; Gerlach, J. W.; Stesmans, A.; Jivanescu, M.; Müller, U.; Vogt, J.; Hilmer, H.; Löper, P.; Künle, M.; Munnik, F.; Nielsch, K.; Zacharias, M.


SiO2 is the most widely used dielectric material but its growth or deposition involves high thermal budgets or suffers from shadowing effects. The low-temperature method presented here (150 °C) for the preparation of SiO2 by thermal atomic layer deposition (ALD) provides perfect uniformity and surface coverage even into nanoscale pores, which may well suit recent demands in nanoelectronics and nanotechnology. The ALD reaction based on 3-aminopropyltriethoxysilane (APTES), water and ozone provides outstanding SiO2 quality and is free of catalysts or corrosive by-products. A variety of optical, structural and electrical properties are investigated by means of infrared spectroscopy, UV-VIS spectroscopy, secondary ion mass spectrometry, capacitance-voltage- and current-voltage-measurements, electron spin resonance, Rutherford backscattering, elastic recoil detection analysis, atomic force microscopy, and variable angle spectroscopic ellipsometry. Many features, such as the optical constants (n, k), optical transmission and surface roughness (1.5 Å) are found to be similar to thermal oxide quality. Rapid thermal annealing (RTA) at 1000°C is demonstrated to significantly improve certain properties, in particular by reducing the etch rate in hydrofluoric acid, oxide charges and interface defects. Besides a small amount of OH-groups and a few atomic per mille of nitrogen in the oxide remaining from the growth and curable by RTA no impurities could be traced. Altogether, the data point to a first reliable low temperature ALD-growth process for silicon dioxide.