| 摘要 |
<p>958,978. Semi-conductor devices. GENERAL ELECTRIC CO. Ltd. Jan. 10, 1962 [Jan. 17, 1961], No. 1972/61. Heading H1K. In a junction transistor comprising a wafer of semi-conductor material 1, of one conductivity type and which is of uniform resistivity except for a layer 2 of relatively low resistivity formed adjacent one major face of the wafer and having emitter 11 and collector 5 regions of opposite conductivity type material extending into the wafer from the faces adjacent and remote from said layer and which are separated by a narrow base region 12, the collector region includes a first portion 9 of relatively large cross-sectional area in planes parallel to the major faces of the wafer and a second portion 6 of relatively small cross-sectional area which extends from said first portion to the layer, the collector electrode 10 being in contact with the first portion over substantially the whole of its area. Wafer 1 of n-type germanium is 40Á thick and has a resistivity of 30 ohm cm., while layer 2 which is formed by diffusing in antimony up to a concentration of 10<SP>17</SP> atoms per c.c. is 7Á thick. An apertured nickel plate 3 acts as the base electrode. The collector region is formed in two stages, the first of which comprises alloying an indium pellet to the wafer at a temperature of 550‹ C., so forming a cylindrical region 6 which penetrates layer 2 to a depth of 0.5Á, and then removing excess indium. An indium disc of much larger diameter than the pellet is then placed on wafer 1 and further alloying is carried out at 450‹ C. to produce a region 9 about 10Ádeep, the surplus indium in this case acting as the collector electrode. An indium pellet 13 is then alloyed to layer 2 at a temperature just below 450‹ C., thus forming the emitter region 11 and leaving a base region 12 having a thickness of 3.5Á The device is encapsulated in a hermeticallysealed envelope (Fig. 5, not shown), which includes a copper portion to which the collector electrode is soldered.</p> |
