Patent GB-1019213-A (GB)
Title: Solid circuits comprising field-effect devices known as gridistors
IPC: H01L29/808
Filed: 1963-08-02
Abstract: 1,019,213. Semi-conductor devices; circuit assemblies. R. C. SUEUR, and S. TESZNER. Aug. 2, 1963 [Aug. 3, 1962], No. 30745/63. Headings H1K and H1R. A solid circuit consists of two series-coupled "gridistors" disposed in a semi-conductor wafer on either side of the cross-piece of an H -shaped region of the wafer of one conductivity type, and two metallized longitudinal strips of semi-conductor material of the opposite type along the legs of the H. Integrated resistors are provided between the anode of one gridistor and one of the strips and between the cathode and gate electrodes and the other of the strips. A " gridistor " consists of a plurality of rodshaped regions of semi-conductor material of one conductivity type, perpendicular to the main faces of the wafer, and embedded in an internal layer of opposite conductivity type, with their ends integral with superficial layers of the same conductivity type as the rods on the main faces of the wafer. The solid circuit amplifier of Fig. 6 is formed by initially diffusing boron through an apertured oxide mask into a wafer of N-type silicon to separate the four N-type zones 28, 29, 30 and 31 and produce the H- region of P-type material. Phosphorus is then diffused into the regions 28 and 29 forming N + -layers as at 32. In each of the regions 28 and 29 a " gridistor " is formed by successive diffusion steps. Connection between the anode 11a and gate 12b is effected through a capacitor 24 formed by extending the N+ zone 32 by a tongue 33 which extends into the P-type region 27. The tongue is then covered with a layer of silicon dioxide which is subsequently covered and completed by a metallized tongue 34. N-type regions 30 and 31 which are formed during the P-type diffusion in the edges of the wafer are metallized and used as earth bar 13 and supply bar 16 (Fig. 4, not shown). Connections between the gridistor electrodes and the bars 13 and 16 is facilitated by provision of resistors 14, 15, 18, 20 and 21 formed by diffusion of phosphorus N + impurity or by the deposition of a conducting ink on the semiconductor surface, e.g. a colloidal carbon material. Input and output terminals are provided by region 25a and 25b and 26a and 26b (Fig. 5, not shown). A flip-flop circuit in integrated form is another embodiment (Fig. 9, not shown) which is similar to the above described amplifier solid-circuit except that it is necessary to insert a biasing bar 51 and so part of the ground-bar 39 is cut away and the corresponding wafer edge is profiled to accommodate it. The two sections 39a and 39b have consequently to be connected externally by a connection 52. Deposited metal contacts 61 and 62 between the cathodes 35c and 36c and the earth bars 39a and 39b (Fig. 8, not shown) may be insulated from the P-type frame by a silicon oxide layer. In fact prior to metallization the whole device may be masked with such a layer and then apertured to define the contact regions for metal deposition. The resistors may alternatively be formed by evaporation of a thin metallic film and any inductive elements required may be produced by depositing a ferromagnetic layer on the semi-conductor crystal and vaporizing a metallized spiral on this layer.