Feasibility of high-data-rate media with Ge-Sb-Te phase-change material

We experimentally studied an optical disk with a large capacity and high da ta-transfer rate that can record high-definition television signals. A high rotation speed was used to achieve the high data-transfer rate. Using Ge-S b-Te phase change material, a carrier-to-noise ratio of about 50dB was achi eved at a linear velocity of 15-30m/s with a 0.4-mum-long mark. High-speed crystallization was necessary to erase recording marks. Therefore, by appro priately designing layers that assist nucleation, we obtained a DC erase ra tio of 29 dB with a 0.4-mum mark and 1-mW power margin for over-25-dB erase ratio at a linear velocity of 18 m/s. Furthermore, the 0.4-mum mark-space repetition jitter was less than 7% even after 1000 cycles. A data transfer rate of 60 Mbps was obtained by optimizing the write strategy using a multi -pulse with an optical system equivalent to that of current digital versati le disk (DVD).