| 摘要 |
PURPOSE:To enable simultaneous data writing on the entire surface, enable a written condition to be maintained for a long time and enable a larger area and a higher density, by a construction wherein a memory medium returned from a second optical characteristic to a first optical characteristic when a bias is applied thereto is clamped by a plurality of electrodes. CONSTITUTION:A superlattice film 3 is provided by carrying out an RF glow discharge decomposition method, a sputtering method, a photo-CVD method or the like using, for example, a mixed gas of SiH4 and B2H6 for a p-layer and similarly using, for example, a mixed gas of SiH4 and PH3 for an n-layer. This process is repeated to periodically providing pnpn...pnp layers so that the thickness of each p-layer and that of each n-layer are substantially equal, thereby obtaining the superlattice film. Writing is conducted by setting the device in a short-circuit condition, and irradiating the device with rays, preferably having a frequency selected in the range from IR rays to UV rays. Though writing may be conducted with a bias applied to the device, the ratio of change in optical characteristic is maximized when the bias is 0. When optical writing is carried out with a bias of 0, the ratio of change in the optical characteristic reaches its maximum. |
