PURPOSE: To rapidly set the film forming condition of a membrane with a stoichiometric ratio composition (Li/Nb=1) by evaluating a compositional ratio Li/Nb using the light absorbing end wavelength measured using an LiNbO3 membrane.
CONSTITUTION: A vacuum chamber 20 is set to a film forming state to set a Knudsen cell 2(Li) and an electron beam heating evaporation source 1 (Nb) to a definite evaporation state. Both shutters 5 are opened to perform the simultaneous vapor deposition of Li and Nb on a monitoring quartz plate 13. The light from a light source 12 is transmitted through the quartz plate 13 during this vapor deposition and the light absorbing end wavelength of the membrane during membrane formation is measured by a spectrophotometer 14 capable of performing measurement over a range from a visible region to an ultraviolet region. Next, the output of the power controller 16 of the evaporation source 1 is controlled by a computer 15 to increase and decrease an emission current and the membrane is formed so as to enter the range of about 310 - 320nm being the light absorbing end wavelength of the stoichiometric ratio composition of LiNbO3. The film forming conditions of the evaporation source 1 and the Knudsen cell 2 are held and a shutter 6 is opened to accumulate the membrane on a substrate 4.
ONO KIMITAKA
OKAMOTO YASUNARI
