Abstract: A CMOS based n-channel metal-insulator-semiconductor field-effect transistor (MISFET) that exhibits a useful negative differential resistance effect is disclosed. The resulting device can be incorporated into a number of useful applications, including as part of a memory device, a logic device, etc.

Abstract: An n-channel metal-insulator-semiconductor field-effect transistor (MISFET) that exhibits a variable threshold voltage is disclosed. The resulting device can be incorporated into a number of useful applications, including as part of a memory device, a logic device, etc.

Abstract: A silicon based semiconductor device and method uses charge trapping to alter a density of carriers available in a channel of a field effect transistor (FET) for conduction. The charge trapping mechanism can be controlled by a source-drain bias voltages applied to the FET, so that the device can be turned off through a control mechanism separate from a gate voltage.

Abstract: A method of making an n-channel metal-insulator-semiconductor field-effect transistor (MISFET) that uses charge trapping for altering channel conductivity characteristics is disclosed. Other suitable and conventional processing steps are used to finalize completion of the fabrication of the charge trapping device so that the entire process is compatible and achieved with CMOS processing techniques, and so that non-charge trapping devices can be formed at the same time in a common sequence of manufacturing operations.

Abstract: An n-channel field effect transistor (FET) with a switchable negative differential resistance (SNDR) characteristic is disclosed. The n-channel SNDR FET is configured as a depletion mode device, and biased so that it operates essentially as a p-channel device. Because the device is n-channel, speed is improved, and processing complexity is reduced when designing and manufacturing large scale circuits. The device achieves a performance comparable to CMOS, and thus is suitable as a replacement for a p-channel pull-up devices in logic gates (including in inverters) and memory cells.

Abstract: A process for forming gate oxides of multiple thicknesses. Oxygen is implanted through a sacrificial oxide into selected regions of a silicon substrate according to a patterned photoresist mask. After stripping the sacrificial oxide, a thermal growth process produces a thicker oxide in the implanted regions than in the non-implanted regions. The oxygen-implanted oxide has excellent quality and thickness differentials of up to 20 Å may be obtained with relatively low oxygen implant doses. In an alternative process, a thin gate oxide may be grown prior to a polysilicon layer deposition, and oxygen is then implanted through the polysilicon according to a patterned photoresist mask. After stripping the photoresist, an anneal increases the thickness of the gate oxide in the implanted regions. In another embodiment, a high dielectric constant dielectric layer is deposited on the substrate prior to polysilicon deposition to limit subsequent silicon oxide growth.

Abstract: A semiconductor device including integrated insulated-gate field-effect transistor (IGFET) elements and one or more negative differential resistance (NDR) field-effect transistor elements, combined and formed on a common substrate. Thus, a variety of circuits, including logic and memory are implemented with a combination of conventional and NDR capable FETs. Because both types of elements share a number of common features, they can be fabricated with common processing operations to achieve better integration in a manufacturing facility.

Abstract: A method of testing/stressing a charge trapping device, such as a negative differential resistance (NDR) FET is disclosed. By operating/stressing a charge trap device during/after manufacture, a distribution of charge traps can be altered advantageously to improve performance.

Abstract: A negative differential resistance (NDR) field-effect transistor element is disclosed, formed on a silicon-based substrate using conventional MOS manufacturing operations. Methods for improving a variety of NDR characteristics for an NDR element, such as peak-to-valley ratio (PVR), NDR onset voltage (VNDR) and related parameters are also disclosed.

Abstract: An integrated circuit is disclosed which includes a variety of NDR devices having different characteristics. The different NDR devices are formed to have different PVRs, different onset NDR voltages, etc. in a common substrate, by controlling various conventional processing operations, such as an implant, an anneal, an insulator film deposition, and the like.

Abstract: A variety of processes are disclosed for controlling NDR characteristics for an NDR element, such as peak-to-valley ratio (PVR), NDR onset voltage (VNDR) and related parameters. The processes are based on conventional semiconductor manufacturing operations so that an NDR device can be fabricated using silicon based substrates and along with other types of devices.

Abstract: A charge trapping device, and a method of forming the same is disclosed. Charge traps are optimally distributed through a trapping region based on controlling various conventional processing operations, such as an implant, an anneal, an insulator film deposition, and the like. In some embodiments, FETs can be configured to include a negative differential resistance (NDR) characteristic when they utilize a particular charge trap energy and distribution.

Abstract: A method of controlling a negative differential resistance (NDR) element is disclosed, which includes altering various NDR characteristics during operation to effectuate different NDR modes. By changing biasing conditions applied to the NDR element (such as a silicon based NDR FET) a peak-to-valley ratio (PVR) (or some other characteristic) can be modified dynamically to accommodate a desired operational change in a circuit that uses the NDR element. In a memory or logic application, for example, a valley current can be reduced during quiescent periods to reduce operating power. Thus an adaptive NDR element can be utilized advantageously within a conventional semiconductor circuit.

Abstract: An active negative differential resistance element (an NDR FET) and a memory device (such as an SRAM) using such elements is disclosed. Soft error rate (SER) performance for NDR FETs and such memory devices are enhanced by adjusting a location of charge traps in a charge trapping layer that is responsible for effectuating an NDR behavior. Both an SER and a switching speed performance characteristic can be tailored by suitable placement of the charge traps.

Abstract: A memory cell using both negative differential resistance (NDR) and conventional FETs is disclosed. A pair of NDR FETs are coupled in a latch configuration so that a data value passed by a transfer FET can be stored at a storage node. By exploiting an NDR characteristic, the memory cell can be implemented with fewer active devices. Moreover, an NDR FET can be manufactured using conventional MOS processing steps so that process integration issues are minimized as compared to conventional NDR techniques.

Abstract: A device and method uses charge trapping to configure and adjust a threshold voltage (Vt) for a field effect transistor (FET). The charge trapping mechanism can be controlled by bias voltages applied to the FET, so that rapid/dynamic changes can be made to Vt without the use of conventional program/erase cycles. The threshold voltage can thus be set as a function of applied operating voltages.

Abstract: A memory device (such as an SRAM) using negative differential resistance (NDR) elements is disclosed. Body effect performances for NDR FETs (and other FETs) that may be used in such device are enhanced by floating a body of some/all the NDR FETs. Various embodiments using common or separate wells for such elements are illustrated to achieve superior body effect performance results, including a silicon-on-insulator (SOI) implementation.

Abstract: A process for forming/configuring a device to include a negative differential resistance (NDR) characteristic is disclosed. In a FET embodiment, an NDR characteristic is implemented by incorporating a dynamic threshold voltage in such device. An onset point for the NDR characteristic is also adjustable during a manufacturing process to enhance the performance of an NDR device.

Abstract: A process for forming a dual mode FET and a logic circuit to include a negative differential resistance (NDR) characteristic is disclosed. In a FET embodiment, an NDR characteristic is selectively enabled/disabled by forming a body contact bias, thus permitting a dual behavior of the device. Larger collections of such FETs can be synthesized to form dual mode logic circuits as well, so that a single circuit can perform more than one logic operation depending on whether an NDR mode is enabled or not.

Abstract: An n-channel metal-insulator-semiconductor field-effect transistor (MISFET) that exhibits negative differential resistance in its output characteristic (drain current as a function of drain voltage) is disclosed. The MISFET includes a dynamically variable and reversible threshold voltage which is controlled by a source-drain bias. A channel region of the MISFET is doped so as to enhance an electric field associated with the source-drain bias, and thus cause charge carriers to tunnel out of the channel and into a trapping region. A net charge in the trapping region results from the source-drain bias which can be used as an additional control mechanism for conduction in the MISFET.