Semiconductor crosspoints for direct replacement of electromechanical switches with high voltage requirements

From studies of telephone exchange systems, specifications for solid-state switches were worked out. Such switches should replace electromagnetic relays with mechanical contacts directly. It was recognized that a sufficiently high breakdown voltage and a low on-resistance are difficult to achieve. Using discrete solid-state devices in hybrid integration with thick-film technology, solutions for crosspoint elements were worked out and tested. Since these elements were not entirely satisfactory from a cost standpoint, the breakdown voltage requirement was relaxed and weak-current crosspoint elements, which can be produced at a very low cost, were realized in MOS technology. Proposals for elements having negative resistance also indicate that solid-state switches can be constructed with negligible on-resistance.