Patent ID: 7462571

Claim:
A film formation method for a semiconductor process for forming a silicon nitride film of silicon nitride or silicon oxynitride doped with an impurity on a target substrate by CVD, by repeating a cycle a plurality of times to laminate thin films formed by respective times, thereby arriving at a film having a target thickness, in a process field, which is configured to be selectively supplied with a first process gas containing a silane family gas, a second process gas containing a nitriding gas, and a third process gas containing a doping gas, and communicates with an exciting mechanism configured to selectively excite the second process gas to be supplied to the process field, the cycle comprising: a first step of performing supply of the first, second, and third process gases to the process field, while not exciting the second process gas by the exciting mechanism; a second step of shutting off supply of the first, second, and third process gases to the process field; a third step of performing supply of the second process gas to the process field while shutting off supply of the first and third process gases to the process field, the third step comprising an excitation period of supplying the second process gas to the process field while exciting the second process gas by the exciting mechanism; and a fourth step of shutting off supply of the first, second, and third process gases to the process field.