| 摘要 |
1,183,170. Semi-conductor devices. HUGHES AIRCRAFT CO. 16 Dec., 1968 [18 Dec., 1967], No. 59709/68. Heading H1K. A layer of semi-conductor material is epitaxially deposited in vacuo and at least a selected portion is simultaneously bombarded with ions of a second material. This method allows parts of an epitaxial layer to be selectively doped during deposition and may also be used to produce abrupt junctions. The epitaxial deposition may be effected by heating a source of the semi-conductor material in vacuo to produce a vapour which condenses on a suitably heated substrate. An ion source directs a beam of ions of the second material on to the substrate as required to dope the deposited layer, and more than one ion source may be utilized simultaneously. The substrate is polished, etched and cleaned before deposition of the layer. The method may be applied to the production of diodes and transistors. A metal base transistor, Figs. 5 and 6 (not shown) is made by epitaxially depositing a layer of silicon and simultaneously ion implanting gold on an N-type substrate to produce the conductive base region. When the desired thickness of base region has been deposited the gold mplantation is stopped and an X-type epitaxial layer is grown. The N-type layer may be doped by implantation of antimony ions or by conventional methods. A varactor diode, Fig. 7 (not shown), is produced on a high conductivity N-type substrate by epitaxially depositing an N-type layer of lower conductivity followed by a P- type layer, both layers being doped by ion implantation. A buried region, Figs. 8 and 9 (not shown), is produced by epitaxially depositing an N-type layer on a substrate followed by a layer comprising a P-type region surrounded by an N-type region, which is itself followed by a further N- type layer which may have a small P-type portion providing a connection to the buried layer. The regions of different conductivity type are produced by selectively implanting impurities in the epitaxial layers as they are grown using two simultaneously energized ion sources. |
