| abstract |
A layer formation method is disclosed which comprises supplying gas to a discharge space, exciting the supplied gas at atmospheric pressure or at approximately atmospheric pressure by applying a high frequency electric field across the discharge space, and exposing a substrate to the excited gas, wherein the high frequency electric field is an electric field in which a first high frequency electric field and a second high frequency electric field are superposed, frequency ω 2 of the second high frequency electric field is higher than frequency ω 1 of the first high frequency electric field, strength V 1 of the first high frequency electric field, strength V 2 of the second high frequency electric field and strength IV of discharge starting electric field satisfy relationship V 1 ≧IV>V 2 or V 1 >IV≧V 2 , and power density of the second high frequency electric field is not less than 1 W/cm 2 . |