Manufacturing method of a semiconductor device including a single crystal semiconductor film, and a semiconductor film including impurity

A method for manufacturing a semiconductor device comprising the steps of:

• forming a first semiconductor film over a substrate having an insulating surface;
• implanting a first conductivity type impurity into a first portion of the first semiconductor film;
• implanting a second conductivity type impurity into a second portion of the first semiconductor film, wherein the second conductivity type impurity is opposite to a conductivity type of the first conductivity type impurity;
• forming an ion separation layer in a region of a predetermined depth below a surface of a single crystal semiconductor substrate by irradiating the single crystal semiconductor substrate with at least one kind of ions generated by plasma excitation of a source gas selected from the group consisting of hydrogen, helium, and halogen, wherein the ions are constituted by the same element;
• after implanting the first conductivity type impurity, bonding the surface of the single crystal semiconductor substrate to the surface of the first portion and the second portion of the first semiconductor film;
• generating a crack in the ion separation layer by heating the bonded single crystal semiconductor substrate and the first portion and the second portion of the first semiconductor film;
• and
• forming a second semiconductor film by separating the single crystal semiconductor substrate at the crack in the ion separation layer with the second semiconductor film left on the first portion and the second portion of the first semiconductor film.