| 摘要 |
A data storage device 12 is described having a storage medium comprising a plurality of storage cells 210, 212, 214, 216, 218, 220, 222, 224 which may each be programmed to one of more than two states. This allows each storage cell to represent more than one data bit. The storage device includes a probe 13, 14, which scans across the surface of the storage medium to program the storage cells by creating perturbations in each cell. The storage device may employ nanotechnology, for instance atomic force microscopy or scanning tunnelling microscopy, and the probe may be a microscopic probe. An array, or plurality, of probes may be used. In one embodiment the perturbations are pits, or dents of variable depth. The storage media 200 may be formed from layers of different materials 202, 204, 206, 208. The materials may have progressively higher melting points. The probe can then be heated to a temperature which allows it to melt though a certain number of layers to form a pit of a predetermined depth. Alternatively the layers of material may have different tensile strengths; the tensile strength of each layer being greater than the last. Pits can then be formed by applying force to the probe tip 14 sufficient to break through or deform one or more of the plurality of layers. A cell, 218, may be left with no perturbation formed in order to represent a further storage state. Once pits are formed they may be erased by heating the probe tip to melt the surrounding material so that it flows into and fills the pit. The storage cells are read by dragging the probe tip across the surface of the storage medium so that it deflects into any pits. Other types of perturbation may include creating or altering the composition of the storage media; altering the crystalline phase of the media; filling or emptying existing electronic states of the media; creating or altering domain structures or polarization states of the media; creating or altering chemical bonds in the media; employing tunnelling effects to move and remove atoms or charge to or from the medium; or storing / removing charge from a particular region. The device enables high density data storage. |
