| 摘要 |
1,161,049. Semi-conductor devices. S. TESZNER. 12 June, 1968 [13 June, 1967; 17 Oct., 1967; 30 Nov., 1967; 21 March, 1968]. No.27981/68. Heading H1K. A multichannel field effect semi-conductor device, or " gridistor," comprises in a wafer of semi-conductor material of one conductivity type, having source 36 and drain 39 regions on its parallel major surfaces, a diffused internal grid 34 of the opposite conductivity type which bounds a number of conductive channels 37, the grid comprising a frame zone 35 from which bands or strips 30 extend, such zone and bands being devoid of channels and having one part 35 within the wafer and a further overlying surface part 52, both parts being in ohmic contact at 32. The bands 30 ensure that the distance, and hence the resistance, between the central channels and the frame zone 35 to which external contact is made is small. To reduce the source-grid input capacitance the resistivity of the epitaxial layer 3 is higher than that of the substrate layer 1 with the source and drain electrodes'as above, or in the case where they are reversed layer 3 has a lower resistivity than layer 1. The semiconductor material is silicon and the dopants used are boron and phosphorus. A number of configurations are disclosed. To prevent the spreading of the grid 34 and hence the constriction of the channels 37 during the diffusion cycles in the later stages of the manufacture of the device the layer 3 has its thickness reduced by etching over those parts where the frame is to be to form a groove 51 into which the part 52 of the frame is diffused, the time to reach a depth at which the submerged part 35 lies being in this case much reduced. A metal layer 54 is then applied in the groove in contact with the frame zone. Alternatively, an impurity which diffuses much more quickly than that used to form the grid may be used, such as aluminium in the case of a boron grid. In an alternative embodiment, Fig. 9 (not shown), the device has no peripheral frame zone, it being replaced by a solid central zone (59) with radiating arms (72). In a further embodiment, Fig. 13 (not shown), five diamond-shaped gridistors are juxtaposed in the form of a quincunx, the frame zones and arms being interconnected.
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