GB983252A - Electrical circuits - Google Patents

Abstract

983,252. Semi-conductor devices. TEXAS INSTRUMENTS Inc. May 1, 1961 [May 2, 1960 (4)], No. 15723/61. Heading H1K. [Also in Division H3]. An electrical circuit comprises a field effect transistor and a junction transistor, the gate being connected to the collector and the drain being directly connected to the base. Fig. 2a shows an N-type body 11 having a P-type diffused layer 12 containing N-type regions 14 and 20. Region 14 is connected to the N-type body 11 to provide the gate electrode for the field effect transistor in which P-region 12 constitutes the channel between source 17 and drain electrodes. N-type region 20 constitutes the emitter of a junction transistor in which part of region 12 constitutes the base and body 11 the collector. The drain of the field effect transistor is thus connected to the base of the bipolar junction transistor since they are formed from the same semi-conductor region. The combined device is equivalent to the circuit shown in Fig. 3 which displays a high input impedance. A modified construction is also described which comprises a central source electrode surrounded by annular electrodes and regions to provide a similar combination. The device may be produced by diffusing gallium into an oxide coated silicon wafer to form a P-type layer and then diffusing phosphorus into selected regions where the oxide coating has been removed. Aluminium is used to provide ohmic contacts to the P-type region. Fig. 6 shows a ring counter circuit employing the transistor arrangement, comprising four bi-stable state stages 48, 42, 43, 44 in which in one state, both transistors are conducting and in the other both are cut off. Initially stage 41 is ON and stages 42, 43, 44 are OFF. Input consisting of a positive pulse is applied to terminal 55 and this has no effect on stage 41 (which is already ON) and is also insufficient to affect stages 43 and 44. The fact that 41 is ON however has conditioned stage 42 by raising potential of its source 17 nearly to the pinch-off limit so that arrival of the input pulse triggers stage 42 into conduction. The resulting fall in potential of the collector 19 of stage 42 is applied via resistor 59 to the source electrode of stage 41 and regenerative action then occurs so that stage 41 reverts to its non- conducting state. Succeeding pulses turn on stages 43, 44 and then 41, and so on in a similar manner. By having only two stages a flip-flop may be provided. Fig. 8 shows a semi-conductor body which comprises the field effect and bipolar transistors and also the resistors 47, 51, 59 and 61 for each stage of the ring counter circuit of Fig. 6. Electrode 91 constitutes the source and electrode 89 the gate of the field effect transistor and electrode 87 and electrode 105 the emitter and collector electrodes of the bipolar transistor. The semi-conductor body comprises N-type zone 71, P-type layers 75 and 77 and N-type zones 79 and 81 penetrating the P-type layer. The semi-conductor material lying between electrodes 83 and 85 constitutes resistance 51, that between electrodes 103 and 105 is resistance 47, that between electrodes 105 and 107 is resistance 59 and that between electrodes 91 and 101 is resistance 61. External connections are made between electrodes 85 and 87 and between the gate and collector electrodes 81 and 105. Electrodes 91 and 87 of each stage are connected respectively to electrodes 107 and 101 of the succeeding stage. Specification 983,275 is referred to.