Ultraviolet assisted injection liquid source chemical vapour deposition (UVILS-CVD) of tantalum pentoxide

Ultraviolet assisted injection liquid source chemical vapour deposition (UVILS-CVD) emerged during 1999 as a new low-temperature dielectric deposition system combining earlier developments in injection liquid source CVD and excimer lamp assisted CVD. While the UVILS-CVD technique is still at an early stage of development, the reported results in the literature indicate that UVILS-CVD is a promising technique for the controlled deposition of ultra-thin high-k metal-oxide dielectrics for deep sub-micron CMOS devices at temperatures as low as 350 °C. As-deposited UVILS-CVD tantalum pentoxide dielectrics have been reported with refractive index values in the range 2.02-2.16, conventional capacitance-voltage characteristics, dielectric constants in the range 18-24, fixed oxide charge content of less than 5x10¹⁰ cm^-2 and breakdown fields higher than 2 MV·cm^-1. Annealing reduces the leakage currents by several orders of magnitude. The main characteristics of the UVILS-CVD technique reported to date In the literature are reviewed.