Abstract: A doped area is formed in the silicon substrate layer of a silicon-on-insulator stack including a silicon substrate, an insulator layer and an silicon active layer, by implanting a species through at least the insulator layer. In one embodiment, the silicon active layer is etched and the species are implanted in the silicon substrate through the exposed insulator layer. Thus, a doped region is formed in the silicon substrate under the areas where the silicon active layer was removed. In another embodiment after etching the silicon active layer, a dielectric layer is formed adjacent to the silicon active layer and on the insulator layer. In this embodiment, the species are implanted over the entire wafer through both the silicon active layer and the insulator layer. In both embodiments, the species are implanted before forming a gate electrode of a transistor.

Abstract: A DMA controller has both a receiving portion and a sending portion and may be used in a modem or other data transmission context. The DMA controller is intended to provide to or receive from data samples on a bus that may or may not be available. For the case when the bus is available, samples of data are either sent to or received from proper memory locations. When the bus is not available, the number of the samples that are missed due to the bus not being available is stored. This count is then used to ensure that the samples that are provided or received when the bus becomes available are stored in or read from the proper location to provide the samples at the proper time. The locations in which the samples were lost are provided with predetermined values.

Abstract: An integrated circuit using silicon-on-insulator (SOI) has most of its transistors with their channels (bodies) floating. Some of the transistors, however, must have their channels coupled to a predetermined bias in order to achieve desired operating characteristics. In order to achieve the needed bias, a contact path is provided in the semiconductor layer of the SOI substrate and under an extension of the gate of the transistor. The extension is separated from the semiconductor layer by an insulator that is thicker than that for most of the transistor but advantageously is the same as that used for some of the thick gate insulator devices used, typically, for high voltage applications. This thicker insulator advantageously reduces the capacitance, but does not increase process complexity because it uses an insulator already required by the process.

Abstract: A process for forming a first transistor of a first conductivity type and a second transistor of a second conductivity type in a semiconductor substrate is disclosed. The substrate has a first well of the first conductivity type and a second well of the second conductivity type. A gate dielectric is formed over the wells. A first metal layer is then formed over the gate dielectric. A portion of the first metal layer located over the second well is then removed. A second metal layer different from said first metal is then formed over the wells and a gate mask is formed over the second metal. The metal layers are then patterned to leave a first gate over the first well and a second gate over the second well. Source/drains are then formed in the first and second wells to form the first and second transistor.