| 摘要 |
PURPOSE:To provide recording and reproducing performance without toxicity by forming a titled element so as to contain a substrate having guide grooves and thin amorphous hydrogenated silicon germanium film as a recording material. CONSTITUTION:The substrate having the guide grooves and the thin amorphous silicon germanium film (thin a-SiGe or a-SiGe:H film) layer as the recording material are provided. The thickness of the recording material layer is not particularly limited and is generally in a 0.005-0.3mum range in terms of recording and reproducing sensitivity, etc. The Si/Ge ratio in the thin a-SiGe film is preferably specified in a 1:9-9:1 range in order to obtain the advantageous recording and reproducing characteristics. The thin a-SiGe film is generally advantageous if said film is so formed that the coefft. of absorption to laser light having 780nm wavelength is about 10<-4>cm<-1>. A high difference in the coefft. of absorption before and after the projection of the laser light is then obtd. The recording element which is safe at the time of handling and use, has the satisfactory recording and reproducing characteristics and permits recording of a large capacity is thus obtd. |
