Patent ID: 7462376

Claim:
A CVD method for forming a silicon nitride film on a target substrate by repeating a predetermined cycle a plurality of times to laminate thin films formed by respective times, thereby arriving at a silicon nitride film having a target thickness, in a process chamber configured to be selectively supplied with a silicon source gas including chlorine, ammonia gas, and ethylene gas, the predetermined cycle, in order, comprising: a first step of supplying the silicon source gas and the ethylene gas to the process chamber while maintaining supply of the ammonia gas to the process chamber in a shut off state; a second step of maintaining supply of the silicon source gas, the ammonia gas, and the ethylene gas to the process chamber in a shut off state; a third step of supplying the ammonia gas to the process chamber while maintaining supply of the silicon source gas and the ethylene gas to the process chamber in a shut off state; and a fourth step of maintaining supply of the silicon source gas, the ammonia gas, and the ethylene gas to the process chamber in a shut off state, in this order, while exhausting gas from inside the process chamber during the first to fourth steps.