INTEGRERAD KRETSANORDNING INNEFATTANDE TVA FELTEFFEKTTRANSISTORER MED ISOLERAT STYRE OCH EN GRINDISOLATORSKYDDSANORDNING.

摘要

1359979 Semi-conductor devices RCA CORPORATION 27 March 1973 [27 March 1972] 14689/73 Heading H1K An integrated circuit device 321 includes IGFETS 121, 141, in a surface 361 of an, e.g. N-type semi-conductor body having respective source and drain regions 381, 391 (P+ ) and source and drain regions 421, 431 (N+) in a diffused, e.g. P-type well; gate electrodes 201, 221 being spaced from the body by insulant layers 441, 451 and N+, P + guard rings being provided. A N+ region 68 of similar conductivity to the body defines an elongated resistor region and is formed simultaneously with regions 421, 431 and is disposed within a P-type region 69 formed simultaneously with the well to give a PN junction 70 between 68, 69 and another 71 between 69 and the body. An N+ region 72 in region 69 defines a PN junction 73, and is connected over a surface conductor 74 to a N+ region 75 defining a PN junction 76 in the well; the gates 201, 221 being interconnected over 77 to region 68 whose other end is connected over 78 to an input terminal (not shown). In detail (Fig. 4) region 68 is elongated at 80 and with end enlargements 81, 82 to which contact is made; which provide high capacitance for PN junction 70 between regions 68, 69; to establish a preset RC time constant for protection means 66 exceeding the expected duration of transients destructive of the gate insulant. In operation (Fig. 5) transistors 121, 141 utilized as a complementary pair inverter are series connected between terminals 161, 181 supplied with voltages V DD , V ss with drains 121, 141 interconnected to output 231, while input 241 is connected to gates 201 221 over resistor 84 defined by region 68. Protective means 66 comprises PN junction 70 which defines a distributed diode represented by diodes 85 . . . 86 whose anodes defined by region 69 are anodic of a further diode 87 at junction 71 of regions 69 and the body, returned to terminal 161. P-type region 69 provides the anode of diode 88 at the PN junction 73 between 69 and 72, backed by diode 89 at PN junction 69 between region 75 and the well; so that diodes 85-86 and 88 are back to back across the insulant of transistor 141. A destructive positive pulse between input 241 and terminal 161 reverse biases diode 85-86 to breakdown at a given voltage. and the voltage across the insulant of transistor 121 is limited. If the transient is positively applied between terminal 181 and input 24, diode 88 conducts at its reverse breakdown voltage and limits voltage across the insulant of transistor 141; the diode 89 preventing clamping of region 69 to V ss during positive input excursions above breakdown. Input voltage is allowed to swing by the full N+ to P breakdown voltage above and below the respective values of V DD and V ss . The device is applicable to the protection of other COS/MOS circuits.