Using metal/Si materials as a recording layer, we have achieved good results for a SR (super resolution) WORM (write-once
read many) disc. Mainly by controlling metal composition and the ratio of metal to Si of recording layer, signal
qualities were greatly enhanced. At the mark length of 75nm, the best CNR (carrier to noise) was about 45dB, write
power was reduced down to 6.5mW, and minimum LFN (low frequency noise) was about 11.7dB. Jitters of single tone
pattern mark for every length marks from 2T through 8T were below 10%. Readout signal was stable over 2.25×105
times reading. So-called "3T-problem" was not observed.