Reactor cleaning processes have been discussed and designed for atomic layer deposition of hafnium oxide film, taking into account the information of silicon epitaxial growth process. One of the key points for designing the reactor cleaning technique is the production of chemical compounds which can be vaporized at low temperatures. Chemical reaction between hafnium oxide and hydrogen chloride was studied and showed that the hafnium chloride was effectively produced by hydrogen chloride gas at temperatures higher than 300°C. The removal of hafnium oxide film deposited in a reactor is expected to be effectively performed at moderately high temperatures.