A transparent electrode composed of ITO(indium-tin oxide), an insulating
layer composed of ZrSiN, an underlayer composed of MgS with a thickness
of 100 to 300 nm, a light emitting layer composed of Mg.sub.1-xCa.sub.xS,
and an insulating layer composed of ZrSiN are formed in this order on a
glass substrate. Electrodes composed of Al are formed on the insulating
layer. The underlayer is formed by sputtering with the substrate
temperature set to room temperature. The light emitting layer is formed
by sputtering with the substrate temperature set to not lower than
100.degree. C.