ALD is a known method for the deposition of thin films. It is a self-limiting, sequential unique film growth technique based on surface reactions that can provide atomic layer control and deposit conformal thin films of materials provided by precursors onto substrates of varying compositions. In ALD, the precursors are separated during the reaction. The first precursor is passed over the substrate producing a monolayer on the substrate. Any excess unreacted precursor is pumped out of the reaction chamber. A second precursor is then passed over the substrate and reacts with the first precursor, forming a monolayer of film on the substrate surface. This cycle is repeated to create a film of desired thickness.
ALD processes have applications in nanotechnology and fabrication of semiconductor devices such as capacitor electrodes, gate electrodes, adhesive diffusion barriers and integrated circuits. Further, dielectric thin films having high dielectric constants (permittivities) are necessary in many sub-areas of microelectronics and optelectronics. The continual decrease in the size of microelectronics components has increased the need for the use of such dielectric films.
Japanese Patent Application No. P2005-171291 reports titanium-based precursors for use in chemical vapor deposition.
Current precursors for use in ALD do not provide the required performance to implement new processes for fabrication of next generation devices, such as semi-conductors. For example, improved thermal stability, higher volatility or increased deposition rates are needed.