| 摘要 |
693,726. Semi-conductor amplifiers. RADIO CORPORATION OF AMERICA. April 18, 1951 [April 21, 1950], No. 9046/51. Class 40 (iv). [Also in Group XL (c)] The current gain characteristic of a transistor is increased by a forming treatment in which a condenser is suddenly discharged between the base and collector electrodes, while biasing voltages are applied to the electrodes, and the collector is spaced at least 0.01 inches from the emitter electrode. Fig. 2 shows a circuit arrangement in which a pulse from charged condenser 31 is applied by means of switch 32 in the reverse current direction between the point contact collector electrode 14 and base electrode 11. The emitter electrode is biased in the forward direction by means of a battery in series with a resistance, and the collector electrode is similarly biased in the reverse direction. The spacing between the emitter and collector electrodes at the time of the pulse is adjusted to about 0.015 inches. Experimental data is furnished to show that the process results in increased current gain, reduced base resistance and reduced output resistance when the treated device is subsequently operated as a normal transistor amplifier, but with the same spacing of about 0.015 inches between the emitter and collector electrodes. The resistivity of the semi-conductor material in this case is assumed to be high, i.e. between 10 and 20 ohm-centimetres. If the resistivity of the semi-conductor material is low, i.e. between 2 and 8 ohmcentimetres, the collector and emitter electrodes may be placed the normal distance apart (i.e. not more than 5 mils.) after the pulsing treatment has been applied at the increased spacing of about 0.015 inches. Alternatively, an auxiliary electrode, spaced at this distance and biased as the emitter, the normal emitter being disconnected, may be used during the pulsing treatment, and then removed or disconnected. Fig. 1 shows a suitable construction for the device. The semi-conductor material may consist of germanium, silicon, boron, selenium or tellurium. |
