| 摘要 |
1,152,489. Transistors. INTERNATIONAL BUSINESS MACHINES CORP. 24 June, 1966 [30 June, 1965], No. 28385/66. Heading H1K. A field effect transistor comprises first and second semi-conductor regions of one conductivity type separated by a cup-shaped third region of the opposite type and an insulated gate electrode over the rim portion of the third region controls current between source and drain electrode on the first and second regions. Fig. 1 shows such a device produced by diffusing boron through an aperture in oxide layer 20 in phosphorus doped N-type silicon body 12 and then diffusing in phosphorus through the same aperture so that cup-shaped P-type region 14 underlying N-type region 18 results; surface concentrations and layer thicknesses are quoted. Alternatively, the layer structure may be produced by epitaxial deposition into a cavity. Source 24, drain 22 and insulated gate electrode 26 are provided, using molybdenum, aluminium or other metal. If desired, heat treatment of the gate electrode in the presence of the oxide layer may be performed after the diffusion processes which result in boron atoms diffusing into the oxide and phosphorus atoms accumulating under the oxide, thus providing a narrow N-type channel at the rim of the P-type cup-shaped region 14; the arrangement can thus provide either a normally ON or a normally OFF field effect transistor. A plurality of transistors in a single wafer may be made by simultaneous diffusion into a plurality of apertures, the processes being controlled to provide both ON and OFF types of devices simultaneously. In another embodiment (Fig. 7, not shown), an ohmic electrode is provided on an extension of the P-type zone 14 (without any conducting surface channel region) so that the device may also be used as a bi-polar transistor, region 14 constituting the base zone. |
