| 摘要 |
1,228,699. Doping semi-conductor layers. NATIONAL CASH REGISTER CO. 10 July, 1969 [15 July, 1968], No. 34737/69. Heading H1K. In making a thin film transistor an accurately doped semi-conductor layer is produced by first depositing a thin layer of impurity on an area between and overlapping source and drain electrodes on a substrate and then depositing the layer of semi-conductor in such a way that during deposition the whole of the impurity is incorporated therein. Typically gold source and drain electrodes are vapour deposited at a spacing of 10Á on a glass ceramic or plastics substrate. A measured quantity of copper is next deposited via a mask to a thickness of 2À19 Š on the inter-electrode gap to overlap the electrodes after which a 1Á thick layer of cadmium selenide is deposited. The thus doped layer, which is of high resistivity, is then covered with a 0À1Á layer of silicon monoxide and an aluminium gate electrode layer and copper wires attached to gate, source, and drain electrodes with silver paint. The measured amount of copper is obtained by evaporating a weighed amount through an aperture on to a tantalum strip which is then used as a source in the deposition step proper. Alternative dopants are silver and gold and cadmium sulphide is an alternative semi-conductor material. |
