Abstract: Improved apparatus and methods for programming anti-fuse devices utilized in programmable semiconductor chips are described. An anti-fuse device circuit is disclosed wherein an anti-fuse device is connected between two programming transistors, and each programming transistor is connected to a separate voltage supply bus and to a control bus network having, for example, a common control bus or separate control buses. Interconnection structures of anti-fuse devices can be formed and a targeted anti-fuse device can be programmed by connecting a programming voltage to the first associated supply bus, by connecting another voltage or ground potential to the second associated supply bus, and by turning on the appropriate control bus line or lines so that the programming transistors conduct to provide a voltage differential across the targeted anti-fuse device.

Abstract: Improved apparatus and methods for programming anti-fuse devices utilized in programmable semiconductor chips are described. An anti-fuse device circuit is disclosed wherein an anti-fuse device is connected between two programming transistors, and each programming transistor is connected to a separate voltage supply bus and to a control bus network having, for example, a common control bus or separate control buses. Interconnection structures of anti-fuse devices can be formed and a targeted anti-fuse device can be programmed by connecting a programming voltage to the first associated supply bus, by connecting another voltage or ground potential to the second associated supply bus, and by turning on the appropriate control bus line or lines so that the programming transistors conduct to provide a voltage differential across the targeted anti-fuse device.

Abstract: Improved apparatus and methods for programming anti-fuse devices utilized in programmable semiconductor chips are described. An anti-fuse device circuit is disclosed wherein an anti-fuse device is connected between two programming transistors, and each programming transistor is connected to a separate voltage supply bus and to a control bus network having, for example, a common control bus or separate control buses. Interconnection structures of anti-fuse devices can be formed and a targeted anti-fuse device can be programmed by connecting a programming voltage to the first associated supply bus, by connecting another voltage or ground potential to the second associated supply bus, and by turning on the appropriate control bus line or lines so that the programming transistors conduct to provide a voltage differential across the targeted anti-fuse device.

Abstract: The field inversion properties of integrated circuits incorporating N-channel MOS devices are improved by using a silicon substrate whose bulk dopant concentration is low, but whose local dopant concentration is high at the field surfaces under the field oxide separating the active surface areas where the individual N-channel MOS devices are formed. The differential doping between surface areas under the field oxide and the active surface areas of the substrate is done by nonselectively ion-implanting boron into the substrate to form a uniform low resistivity layer, removing selected portions of the low resistivity layer to expose the unimplanted, high resistivity substrate and forming the active devices at the unimplanted substrate portions. As an option, the unimplanted surface portion can be doped to an intermediate dopant concentration to improve performance. The remaining pattern of the low resistivity layer is covered with field oxide.

Abstract: The field inversion properties of integrated circuits incorporating N-channel MOS devices are improved by using a silicon substrate whose bulk dopant concentration is low, but whose local dopant concentration is high at the field surfaces under the field oxide separating the active surface areas where the individual N-channel MOS devices are formed. The differential doping between surface areas under the field oxide and the active surface areas of the substrate is done by nonselectively ion-implanting boron into the substrate to form a uniform low resistivity layer, removing selected portions of the low resistivity layer to expose the unimplanted, high resistivity substrate and forming the active devices at the unimplanted substrate portions. As an option, the unimplanted surface portion can be doped to an intermediate dopant concentration to improve performance. The remaining pattern of the low resistivity layer is covered with field oxide.