US Patent 9238865 Multiple vapor sources for vapor deposition

A vapor deposition method and apparatus including at least two vessels containing a same first source chemical. A controller is programmed to simultaneously pulse to the reaction space doses or pulses of a gas from the vessels, each of the doses having a substantially consistent concentration of the first source chemical. The apparatus may also include at least two vessels containing a same second source chemical. The controller can be programmed to simultaneously pulse to the reaction space doses or pulses of a gas from the vessels containing the second source chemical, each of the doses having a substantially consistent concentration of the second source chemical. The second source chemical can be pulsed to the reaction space after the reaction space is purged of an excess of the first source chemical.