295 results about "Impact ionization" patented technology

A single transistor DRAM cell is formed in a SOI substrate so that the DRAM cells are formed in bodies that are electrically isolated from each other. Each cell has doped regions that act as source and drain contacts. Between the drain contact and the body is a region, which aids in impact ionization and thus electron/hole formation during programming that is the same conductivity type as the body but of a higher concentration than the body. Adjacent to the source contact and to the body is a region, which aids in diode current during erase, that is the same conductivity type as the source contact but of a lower concentration than the source contact.

Memory elements, switching elements, and peripheral circuits to constitute a nonvolatile memory are integrally formed on a substrate by using TFTs. Since semiconductor active layers of memory element TFTs are thinner than those of other TFTs, impact ionization easily occurs in channel regions of the memory element TFTs. This enables low-voltage write/erase operations to be performed on the memory elements, and hence the memory elements are less prone to deteriorate. Therefore, a nonvolatile memory capable of miniaturization can be provided.

A DRAM memory cell uses a single transistor to perform the data storage and switching functions of a conventional cell. The transistor has a floating channel body which stores a potential that corresponds to one of two digital data values. The transistor further includes a gate connected to a first word line, a drain connected to a second word line, and a source connected to a bit line. By setting the word and bit lines to specific voltage states, the channel body stores a digital one potential as a result of impact ionization and a digital zero value as a result of forward bias of body-to-source junction.

There is provided a semiconductor device having a new structure which allows a high reliability and a high field effect mobility to be realized in the same time. In an insulated gate transistor having an SOI structure utilizing a mono-crystal semiconductor thin film on an insulating layer, pinning regions are formed at edge portions of a channel forming region. The pinning regions suppress a depletion layer from spreading from the drain side and prevent a short-channel effect. In the same time, they also function as a path for drawing out minority carriers generated by impact ionization to the outside and prevent a substrate floating effect from occurring.

An active pixel sensor is operated with voltages that exceed the nominal operating voltages for a particular integrated circuit process. Voltages that exceed the nominal operating voltages are employed during the reset, integration and readout periods in the operating cycle of the active pixel sensor. The lower limit of the voltage representing the capture of photocharge in the active pixel sensor is fixed by setting the voltage applied to the gate of a reset transistor in the active pixel sensor to a level during integration which prevents the voltage across the dielectric of a transfer transistor from exceeding a preselected value. Read disturb caused by impact ionization current from a readout transistor to a storage node is reduced by lowering the voltage applied to the drain of a readout transistor to reduce the Vds of the readout transistor at the start of a readout period.

A field effect transistor comprising a silicon containing body is provided. After formation of a gate dielectric, gate electrode, and a first gate spacer, a drain side trench is formed and filled with a wide band gap semiconductor material. Optionally, a source side trench may be formed and filled with a silicon germanium alloy to enhance an on-current of the field effect transistor. Halo implantation and source and drain ion implantation are performed to form various doped regions. Since the wide band gap semiconductor material as a wider band gap than that of silicon, impact ionization is reduced due to the use of the wide band gap semiconductor material in the drain, and consequently, a breakdown voltage of the field effect transistor is increased compared to transistors employing silicon in the drain region.

A semiconductor memory cell includes a floating body region configured to be charged to a level indicative of a state of the memory cell selected from at least first and second states. A first region of the memory cell is in electrical contact with the floating body region. A second region of the memory cell is spaced apart from the first region and is also in electrical contact with the floating body region. A gate is positioned between the first and second regions. A back-bias region is configured to generate impact ionization when the memory cell is in one of the first and second states, and the back-bias region is configured so as not to generate impact ionization when the memory cell is in the other of the first and second states.

In a method for inhibiting space charge-related effects in an ion source, an electron beam is directed into a chamber to produce ions from sample material in the chamber. A voltage pulse is applied to the chamber to perturb an electron space charge present in the chamber. The ion source may be an electron impact ionization (EI) apparatus. The ion source may operated in conjunction with a mass spectrometry system.

There is provided a semiconductor device having a novel structure in which high reliability and high field effect mobility can be simultaneously achieved. In an insulated gate transistor formed on a single crystal silicon substrate, pinning regions 105 and 106 are formed at the ends of a channel formation region 102. The pinning regions 105 and 106 suppress the expansion of a depletion layer from the drain side to prevent a short channel effect. In addition, they also serve as a path for extracting minority carriers generated as a result of impact ionization to prevent breakdown phenomena induced by carrier implantation.

Characteristics of a nonvolatile semiconductor memory device are improved. The memory cell comprises: an ONO film constituted by a silicon nitride film SIN for accumulating charge and by oxide films BOTOX and TOPOX disposed thereon and thereunder; a memory gate electrode MG disposed at an upper portion thereof; a select gate electrode SG disposed at a side portion thereof through the ONO film; a gate oxide film SGOX disposed thereunder. By applying a potential to a select gate electrode SG of a memory cell having a source region MS and a drain region MD and to the source region MS and by accelerating electrons flowing in a channel through a high electric field produced between a channel end of the select transistor and an end of an n-type doped region ME disposed under the memory gate electrode MG, hot holes are generated by impact ionization, and the hot holes are injected into a silicon nitride film SIN by a negative potential applied to the memory gate electrode MG, and thereby an erase operation is performed.

One embodiment of a semiconductor device according to the present invention includes a substrate, a base compound semiconductor layer layered on the substrate to form a base, a channel defining compound semiconductor layer layered on the base compound semiconductor layer to define a channel, and an impact ionization control layer that is layered within a layering range of the base compound semiconductor layer and controls the location of impact ionization, wherein the base compound semiconductor layer is formed of a first compound semiconductor, the channel defining compound semiconductor layer is formed of a second compound semiconductor, and the impact ionization control layer is formed of a third compound semiconductor that has a smaller band gap than the first compound semiconductor.

A PMOS device can be designed and manufactured in accordance with the invention to locate its drain junction breakdown point and maximum impact ionization point to reduce or eliminate drain breakdown voltage walk-in. In some embodiments, the drain junction breakdown point and maximum impact ionization point are located sufficiently far from the gate that the device exhibits no significant drain breakdown voltage walk-in. The device can be a high voltage power transistor having an extended drain region including a P-type lightly doped drain (P-LDD) implant, with drain junction breakdown and maximum impact ionization points appropriately located by controlling the implant dose employed to produce the P-LDD implant. Other aspects of the invention are methods for designing a PMOS device including by determining relative locations of the gate and at least one of the drain junction breakdown and maximum impact ionization points to reduce drain breakdown voltage walk-in, and methods for manufacturing integrated circuits including any embodiment of the PMOS device of the invention.

According to some embodiments, systems and methods for surface impact ionization of liquid phase and aerosol samples are provided. The method includes accelerating a liquid or aerosol sample, colliding the sample with a solid collision surface thereby disintegrating the sample into both molecular ionic species (e.g., gaseous molecular ions) and molecular neutral species (e.g., gaseous sample), and transporting the disintegrated sample to an ion analyzer. Some embodiments of the method further comprise discarding the molecular neutral species. Such embodiments transport substantially only the molecular ionic species to the ion analyzer.

An electronic system includes a three terminal device having a light emitting portion and a magnetically sensitive portion. The magnetically sensitive portion is for modulating light emission from the light emitting portion. The device is a spin valve transistor having a light-emitting quantum well in its collector. The device can convert a magnetic digital signal to both an electrical digital signal and an optical digital signal, wherein either or both of these signals can be provided as a device output. The magnetically sensitive portion of the device is formed of a pair of magnetically permeable layers. When the layers are aligned electron current can pass through with sufficient energy to reach a quantum well where they recombine, generating light. The device may be used to read a magnetic storage medium, such as a disk drive. Or it can be used to provide a display or a memory array composed of single device magnetic write, optical read memory cells. Amplification can be provided to the transistor by adjusting the collector base voltage to provide secondary electrons by impact ionization to provide greater electron current and a correspondingly larger optical emission signal.

An avalanche photodiode including a multiplication layer is provided. The multiplication layer may include a well region and a barrier region. The well region may include a material having a higher carrier ionization probability than a material used to form the barrier region.

A charge injection method for improve efficiency of generating hot carrier, wherein, for example, electrons are injected at writing and holes are injected at erasing to a charge storage layer of a memory transistor. A positive voltage is applied to the drain region by using a voltage of the source region as a reference, and a voltage having a polarity in accordance with charges to be injected is applied to a gate electrode. A voltage having a voltage value between a source voltage and a drain voltage for turning on a diode made by an N-type source region and a P-type body region is applied to the body region. Then a parasitic bipolar transistor turns on, consequently, impact ionization arises on the drain side and an injection charge amount increases.

A nonvolatile memory cell is provided. The cell has a charge filter, a tunneling gate, a ballistic gate, a charge storage layer, a source, and a drain with a channel defined between the source and drain. The charge filter permits transporting of charge carriers of one polarity type from the tunneling gate through the blocking material and the ballistic gate to the charge storage layer while blocking the transport of charge carriers of an opposite polarity from the ballistic gate to the tunneling gate. Further embodiments of the present invention provide a cell having a charge filter, a supplier gate, a tunneling gate, a ballistic gate, a source, a drain, a channel, and a charge storage layer. The present invention further provides an energy band engineering method permitting the memory cell be operated without suffering from disturbs, from dielectric breakdown, from impact ionization, and from undesirable RC effects.

The present invention relates to an impact ionisation avalanche transit time (IMPATT) diode device comprising an avalanche region and a drift region, wherein at least one narrow bandgap region, with a bandgap narrower than the bandgap in the avalanche region, is located adjacent to or within the avalanche region in order to generate within the narrow bandgap region a tunnel current which is injected into the avalanche region. This improves the predictability with which a current can be injected into the avalanche region and enables a relatively narrow pulse of current to be injected into the avalanche region in order to enable a relatively noise free avalanche multiplication. The narrow bandgap region may be located between a heavily doped contact region and the avalanche region and is preferably arranged to generate a tunnel current at the peak reverse bias applied to the diode.