Patent GB-1331279-A (GB)
Title: Transistor voltage amplifier
IPC: H01L27/082
Filed: 1970-11-25
Abstract: 1331279 Integrated transistor voltage amplifiers PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 25 Nov 1970 [28 Nov 1969] 56068/70 Heading H3T [Also in Division H1] In an integrated transistor voltage amplifier comprising a first vertical transistor 1a, Fig. 1 acting as a voltage amplifier for signals applied to its base, the collector circuit of the transistor 1a incoudes at least one rectifying junction 2a which serves as the collector load of the first transistor, the rectifying junction is so connected that the collector current of the first transistor flows through the rectifying junction in the forward direction of the junction, a directbias current I3 is supplied to the collector of the first transistor 1a through the emitter-collector path of a second lateral transistor 3 of opposite conductivity type to the first transistor, the second transistor 3 has a base region 20, Fig. 2 of one conductivity type and an emitter region 21 and at least two collector regions 23, 24, 25 of the other conductivity type, one 25 of which is conductively connected to the base region 20 of the second transistor, the base region surrounds these collector regions within the semi-conductive body, and the configurations of these regions is such that the base and collector currents of the second transistor 3 control the collector current of the first transistor 1a such that the direct-bias current I3 is larger than the current I2 flowing through the rectifying junction. The action of the transistor 3 is to increase the dynamic resistance of the diodes 2a, 2b so as to provide larger voltage amplification. The non-linearity between the emitter current and the emitter-base voltage of a transistor 1a, 1b is compensated for by the rectifying junction provided by the diode 2a, 2b so as to provide linear amplification. The input voltage + Vi, - Vi to be amplified are applied in push pull. The inputs ŒVi may be cross coupled to the outputs Œ Vu so as to obtain an Eccles-Jordan type trigger. In a modification (Fig. 3, not shown) the anodes of the diodes 2a, 2b are connected to a constant potential and a transistor (11) connected as a diode shunts the base emitter path of transistor (10). In a further modification the diodes 2a, 2b are each replaced by the emitter-collector path of a transistor of the same conductivity type as transistors 1a, 1b which has its base electrode connected to a constant potential. The diodes 2a, 2b may be Schottky diodes. The integrated circuit arrangement of Fig. 1 consists of three NPN vertical transistors 1a, 1b, 10 on three isolated islands 14, 15 and 16, Fig. 2 of a semi-conductor body. Each island has a P-type base 17 and an N-type emitter 18 and a collector 19 produced simultaneously with the emitter. A remaining island 20 contains the lateral PNP transistor 3 with contact opening 22 in an insulating layer coated on to the surface of the semi-conductor body and has an emitter 21 and collectors 23, 24, 25. N-type regions 26, 27 together with region 25 form the two PN d odes 2a, 2b. Through an opening 29 in the insulating layer and a metal layer 30 the collector region 25 is short circuited to the base region of the lateral transistor in the form of the island 20. A buried layer may be provided beneath the emitter region 21. The lateral transistor may alternatively have at least one circular or dot shaped emitter around which at least one collector is arranged. Alternatively the integrated circuit may be formed on a P-type substrate on which may be diffused at least one buried layer and an N-type epitaxial layer. Then phosphorus and boron may be diffused by photolithographic and masking techniques to produce isolating regions and the semi-conductor regions, the boron providing the regions 17, 21, 23, 24 and 25.