A method and apparatus for estimating a height of an epitaxially grown semiconductor material in other semiconductor devices. An inspection target surface of the disk member is irradiated with light beams, and the light beams reflected from or penetrating the inspection target surface are received by a line camera in which a multiplicity of pixels are arranged in lines towards the outer periphery from the center of the disk member. The plasma torch likewise produces the required energy environment, but, unlike the flame, no oxidizer is needed so materials stable in only very low oxygen partial pressures can be formed. By way of example, a compensation line with a feedback operational amplifier can be used for identically altering the electrical potentials on the conductors. The large-thrust linear motor assists the repulsion force by applying a thrust exceeding the repulsion force to the stage to increase the facing area of the pair of magnets of the same polarity. The invention further relates to a process for the production of the film.