| 摘要 |
PURPOSE:To enable extremely easy and inexpensive manufacture of a large-sized disc and to permit long-time recording and reproducing by forming an insulating film having an electric charge accumulating function on a polycrystalline or amorphous semiconductor substrate having <=20mum thickness. CONSTITUTION:A semiconductor disc is formed by forming an extremely thin amorphous silicon layer 2 having <=20mum, for example 1mum thickness on a metallic substrate 1, and forming successively an SiO2 layer 3 having about 20Angstrom thickness and Si3N4 having about 300Angstrom thickness thereon. A voltage signal 6 corresponding to the information signal to be recorded is impressed between a conductive recording stylus 5 and the substrate 1 and the electric charge in the amorphous silicon substrate corresponding to the impressed signal voltage is transferred through the film 3 by a tunnel effect to the Si3N4 film 4 and is recorded in the form of successive trapping of the electric charge. The capacity Co of the Sn3N4 film is always constant but capacity Cv of the depletion layer changes and the thickness tm of the amorphous depletion layer changes with the accumulating condition of the charge in the Si3N4 film, i.e., the recording condition and therefore the reading out of information is accomplished by detecting the change in the capacity Cv of the depletion layer. |
