PURPOSE: To prevent initial plasma damage caused by the on/off of plasma and maintain excellent film characteristics by constituting the structures, etc., of carrying paths and film forming rooms so as to place a substrate in a plasma atmosphere from the beginning to the end of film formation.

CONSTITUTION: A glass substrate 113 is carried to an N layer film forming room 102 and the substrate 113 is heated. Raw gas 118 is introduced to the film forming room 102, a high frequency power source 107 is turned on and a film is formed. At that time, a shield 111 is grounded and plasma is concentrated between the substrate 113 and an electrode 109. When the N layer film formation is completed, the pressure in an I layer film forming room 103 is permitted to be the same as the pressure in the N layer film forming room 102. The high frequency power source 108 of the I layer film forming room 103 is turned on and hydrogen plasma is generated between a high frequency electrode 110 and a auxiliary electrode 117. Plasma is also filled in a gate valve 105. Thus, a growing surface and the interfaces of N/I and I/P are always in the hydrogen plasma atmosphere from the start of the N layer film formation to the completion of P layer film formation and a non-single crystal semiconductor device is manufactured.