149 results about "Electron avalanche" patented technology

A photodiode is provided by the invention, including an n-type active region and a p-type active region. A first one of the n-type and p-type active regions is disposed in a semiconductor substrate at a first substrate surface. A second one of the n-type and p-type active regions includes a high-field zone disposed beneath the first one of the active regions at a first depth in the substrate, a mid-field zone disposed laterally outward of the first active region at a second depth in the substrate greater than the first depth, and a step zone connecting the high-field zone and the mid-field zone in the substrate.

The present invention provides a highly sensitive, thin detector useful for observing low-voltage, high-resolution SEM images, and provides a charged particle beam application apparatus based on such a detector. The charged particle beam application apparatus includes a charged particle irradiation source, a charged particle optics for irradiating a sample with a charged particle beam emitted from the charged particle irradiation source, and an electron detection section for detecting electrons that are secondarily generated from the sample. The electron detection section includes a diode device that is a combination of a phosphor layer, which converts the electrons to an optical signal, and a device for converting the optical signal to electrons and subjecting the electrons to avalanche multiplication, or includes a diode device having an electron absorption region that is composed of at least a wide-gap semiconductor substrate with a bandgap greater than 2 eV.

A photodiode array includes a plurality of arrayed individual diode devices. The arrayed diode devices include at least one active photodiode and at least one reference diode. A bias control circuit for the array monitors operation of the reference diode at an applied first bias voltage and adjusts that applied first bias voltage until optimal reference diode operation is reached. A second bias voltage having predetermined relationship to the first bias voltage is applied to the active photodiode to optimally configure array operation. More specifically, an operational characteristic of the reference diode at the first bias voltage is monitored and compared to a reference value. As a result of this comparison, the circuit adjusts the applied first and second bias voltage in order to drive the reference diode measured characteristic to substantially match the reference value. The operational characteristic that is measured may comprise reference diode responsivity or reference diode output current, and may be based on either electrical or optical device operation. Each avalanche photodiode semiconductor structure may have a conventional reverse biased pn junction semiconductor structure providing a high field region as is well known in the art. An enhanced semiconductor structure may also be utilized wherein a heavily doped layer that is physically separate from the pn junction is also included to provide a source of charge carriers that are swept into the high field region.

With the object of providing a high-speed high-sensitivity planar-type avalanche photodiode (APD) that has high reliability, great manufacturing tolerance and a wide dynamic range, there is presented a planar-type avalanche photodiode, having on a semiconductor substrate a layered structure comprising specific 6 layers, a specific conductive-type acquired region in a peripheral section of a photo-sensitive region and a specific ring-shaped isolation trench region in said photo-sensitive region, wherein a ring-shaped region of the second conductive-type semiconductor cap layer that is inscribed in said ring-shaped isolation trench and located in the periphery of the photo-sensitive region is formed thin to have a thickness equal to or less than the thickness of said semiconductor multiplication layer, and the first conductive-type semiconductor field buffer layer located directly under the ring-shaped cap region, together with a peripheral region in the field buffer layer, is formed to have a lower carrier concentration than the first conductive-type field buffer layer in said photo-sensitive region.

An avalanche photodiode detector is provided. The avalanche photodiode detector comprises an absorber region having an absorption layer for receiving incident photons and generating charged carriers; and a multiplier region having a multiplication layer; wherein the multiplier region is on a mesa structure separate from the absorber region and is coupled to the absorber region by a bridge for transferring charged carriers between the absorber region and multiplier region.

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 high voltage diamond based switching device capable of sustaining high currents in the on state with a relatively low impedance and a relatively low optical switching flux, and capable of being switched off in the presence of the high voltage being switched. The device includes a diamond body having a Schottky barrier contact, held in reverse bias by the applied voltage to be switched, to an essentially intrinsic diamond layer or portion in the diamond body, a second metal contact, and an optical source or other illuminating or irradiating device such that when the depletion region formed by the Schottky contact to the intrinsic diamond layer is exposed to its radiation charge carriers are generated. Cain in the total number of charge carriers then occurs as a result of these charge carriers accelerating under the field within the intrinsic diamond layer and generating further carriers by assisted avalanche breakdown.

The present invention changes layer polarities of an epitaxy structure of an avalanche photodiode into n-i-n-i-p. A transport layer is deposed above an absorption layer to prevent absorbing photon and producing electrons and holes. A major part of electric field is concentrated on a multiplication layer for producing avalanche and a minor part of the electric field is left on the absorption layer for transferring carrier without avalanche. Thus, bandwidth limit from a conflict between RC bandwidth and carrier transferring time is relieved. Meanwhile, active area is enlarged and alignment error is improved without sacrificing component velocity too much.

The invention discloses a high-gain AlGaN ultraviolet avalanche photodetector which structurally and sequentially comprises components from bottom to up: an AlN template layer, an AlxGal-xN buffer layer, an n type AlxGal-xN layer, an i type AlyGal-yN absorbing layer, an n type AlyGal-yN separating layer, an i type AlyGal-yN multiplication layer, a p type AlzGal-zN layer and a p type GaN layer, wherein an n type ohmic electrode is led out from the n type AlxGal-xN layer, a p type ohmic electrode is led out from the p type GaN layer, x is larger than y, y is larger than z, and z is larger than 0. The invention further discloses a preparation method of the high-gain AlGaN ultraviolet avalanche photodetector. The high-gain AlGaN ultraviolet avalanche photodetector adopting an SAM (security account manager) structure can obviously reduce impressed voltage and dark current during APD (avalanche photodiode) avalanche breakdown, and facilitates the increase of APD avalanche multiplication factors.

A novel use of a solid state light detector with a low impedance substrate is described. Light that enters the substrate after traversing the antireflective layer creates an electron-hole pair. The electrons are collected in a crystalline epitaxial layer that spans the space charge region, or depletion layer. A high electric field accelerates free electrons inside the depletion region. The electrons collide with the lattice to free more holes and electrons resulting from the presence of an n-p junction, or diode. The diode is formed by placing the crystalline layer which has positive doping in close proximity with the electrodes which have negative doping. The continual generation of charge carriers results in avalanche multiplication with a large multiplication coefficient. During the avalanche process, electrons can be collected enabling light detection. A resistive layer is used to quench, or stop, the avalanche process.

A double quench circuit for an avalanche current device is provided in which the circuit includes an avalanche current device having a first terminal responsive to a bias voltage to reverse bias the avalanche current device above its avalanche breakdown voltage. A first quench circuit is responsive to the bias voltage and coupled to the first terminal of the avalanche device for reducing the amount of the avalanche current passing through the avalanche device. A second quench circuit is coupled to a second terminal of the avalanche device for reducing the amount of the avalanche current passing through the avalanche device.

The present invention provides a method of treating an ocular disease in a subject. In a first step, a nucleic acid is introduced into cells or a tissue. The nucleic acid is introduced by electron avalanche transfection. With this technique, a high electric field induces a vapor bubble and plasma discharge between an electrode and the surrounding medium. The formation of a vapor bubble generates mechanical stress. Plasma discharge through the ionized vapor in the bubble enables connectivity between the electrode and the surrounding medium, so that mechanical stress and electric field are applied simultaneously, which results in permeabilization of the cells or tissue. This permeabilization in turn allows the nucleic acid to enter the cell or tissue. Cells or tissue containing the nucleic acid are then transplanted into an ocular region of the subject.

The photo detector array is configured to generate pulses with short rise and fall times because each Geiger mode avalanche photodiode includes an anode contact, a cathode contact, an output contact electrically insulated from the anode and cathode contacts, a semiconductor layer, and at least one shield or metal structure in the semiconductor layer capacitively coupled to the semiconductor layer and coupled to the output contact. The output contacts of all Geiger mode avalanche photodiodes are connected in common and are configured to provide for detection of spikes correlated to avalanche events on any avalanche photodiode of the array.

The invention provides a CMOS single-photon avalanche diode specific to long-wave-band weak light. According to the specific structure, a deep N well is manufactured on a P type substrate; next, a P type heavily doped region is manufactured in the deep N well; a PN junction is formed by a P+ layer and the deep N well to be used as an avalanche multiplication region; the P+ region is surrounded bya lightly doped P well to be used as a protection ring; and after incident light comes to a device, the deep N well region in a medium electric field strength is absorbed, and the generated photon-generated carriers move towards an avalanche multiplication region of a strong electric field region. Electron holes generated by light of relatively long waveband are formed in a relatively deep position of the device, so that the light signals can be detected effectively by the deep N well; by taking the deep N well / P substrate as a shielding diode, diffusion of the substrate photon-generated carriers to the PN junction can be prevented, thereby reducing influence of diffusion of substrate slow photon-generated carriers to the response speed of a photoelectric detector; and the absorption efficiency of the device in a long waveband can be improved.

An avalanche photodiode including a first electrode; and a substrate including a first semiconductor layer of a first conduction type electrically connected to the first electrode, in which at least an avalanche multiplication layer, a light absorption layer, and a second semiconductor layer of a second conduction type with a larger band gap than the light absorption layer are deposited on the substrate. The second semiconductor layer is separated into inner and outer regions by a groove formed therein, the inner region electrically connected to a second. With the configuration, the avalanche photodiode has a low dark current and high long-term reliability. In addition, the outer region includes an outer trench, and at least the light absorption layer is removed by the outer trench to form a side face of the light absorption layer. With the configuration, the dark current can be further reduced.

An avalanche photodiode detector is provided. The avalanche photodiode detector comprises an absorber region having an absorption layer for receiving incident photons and generating charged carriers; and a multiplier region having a multiplication layer; wherein the multiplier region is on a mesa structure separate from the absorber region and is coupled to the absorber region by a bridge for transferring charged carriers between the absorber region and multiplier region.

The vertical silicon photomultiplier according to the present invention includes a trench electrode and a PN-junction layer perpendicular to the trench electrode forms and can maximize the quantum efficiency at optical wavelengths, 200˜900 nm in such a way that: it generates electric fields horizontal thereto, by applying a reverse bias voltage to between the trench electrode and the PN junction layer, so that, although ultraviolet light does not reach the PN-junction layer but is incident on the surface, electron-hole pairs can be produced by the horizontally generated electric fields although and an avalanche breakdown can be thus generated, and it allows ultraviolet light, capable of being transmitted to a relatively deep depth, to react with the PN-junction layer.

The present invention changes layer polarities of an epitaxy structure of an avalanche photodiode into n-i-n-i-p. A transport layer is deposed above an absorption layer to prevent absorbing photon and producing electrons and holes. A major part of electric field is concentrated on a multiplication layer for producing avalanche and a minor part of the electric field is left on the absorption layer for transferring carrier without avalanche. Thus, bandwidth limit from a conflict between RC bandwidth and carrier transferring time is relieved. Meanwhile, active area is enlarged and alignment error is improved without sacrificing component velocity too much.

The invention provides an ultraviolet avalanche photo-detector which comprises a silicon substrate (1), a silicon-based avalanche layer (2), a buffering layer (3), a nucleating layer (4) and an absorbing layer (5) from bottom to top. Different from a conventional AlGaN material grows on sapphire or SiC substrate, the ultraviolet avalanche photo-detector is formed in the mode that the buffering layer and the nucleating layer grow on a silicon base, an AlGaN material serves as the absorbing layer, response to ultraviolet light wave bands is effectively improved, the silicon substrate is low in cost, large in single-crystal size and high in quality, and has small dark currents and low noise, and the avalanche layer is made of a silicon material and has low avalanche breakdown voltage. Ultraviolet light enters AlGaN in a normal incidence mode to excite photo-production electron-hole pairs, under action of an external electric field, a single current carrier (electrons) enters the silicon-based avalanche layer to trigger avalanche gain, an absorbing area and an avalanche area can be separated, and the ultraviolet avalanche photo-detector has low avalanche breakdown voltage, high gain, low noise and high bandwidth, and has a wide application range.

The present invention provides a method of treating an ocular disease in a subject. In a first step, a nucleic acid is introduced into cells or a tissue. The nucleic acid is introduced by electron avalanche transfection. With this technique, a high electric field induces a vapor bubble and plasma discharge between an electrode and the surrounding medium. The formation of a vapor bubble generates mechanical stress. Plasma discharge through the ionized vapor in the bubble enables connectivity between the electrode and the surrounding medium, so that mechanical stress and electric field are applied simultaneously, which results in permeabilization of the cells or tissue. This permeabilization in turn allows the nucleic acid to enter the cell or tissue. Cells or tissue containing the nucleic acid are then transplanted into an ocular region of the subject.

A detector for detection of ionizing radiation, an apparatus for use in planar beam radiography, comprising such a detector, and a method for detecting ionizing radiation. The detector includes a chamber filled with an ionizable medium, at least one first electrode arrangement provided in said chamber where said at least one first electrode arrangement includes an electron avalanche amplification unit, said electron avalanche amplification unit including at least one avalanche cathode and at least one avalanche anode between which a voltage is to be applied for creation of an electric field for avalanche amplification, and at least one arrangement of read-out elements for detection of electron avalanches, wherein said at least one avalanche cathode has at least one hole or opening, wherein an area of said at least one hole or opening in the avalanche cathode is bigger than an area of at least one associated anode as seen from above and where said at least one anode is centered with respect to said at least one hole or opening in the avalanche cathode. A radiation entrance is provided so that radiation enters the conversion volume between the first and second electrode arrangements. In order to achieve well-defined avalanches, the electron avalanche amplification unit includes avalanche regions. The detector, apparatus and method is advantageous since it prevents the formation of harmful sparks.

The invention relates to an avalanche photodiode having enhanced gain uniformity enabled by a tailored diffused p-n junction profile. The tailoring is achieved by a two stage doping process incorporating a solid source diffusion in combination with conventional gas source diffusion. The solid source diffusion material is selected for its solubility to the dopant compared to the solubility of the multiplication layer to dopant. The solid source has a diameter between the first and second diffusion windows. Thus, there are three distinct diffusion regions during the second diffusion. The dopant in the multiplication layer at the edge region, the dopant from the solid source material with a relatively higher dopant concentration (limited by the solubility of the dopant in the solid source material) at the intermediate region, and the central region exposed to an infinite diffusion source from the solid source material as it is continually charged with new dopant from the external gas source. The result is that both the dopant concentration and the diffusion depth decrease gradually from the center to the edge of the device. This tailored diffusion profile enables control of the electric field distribution such that edge breakdown is suppressed.

The invention discloses an avalanche photodetector and a method for increasing high frequency characteristics of the avalanche photodetector. The avalanche photodetector is used for detecting target detecting light and comprises an absorbing layer (8), a first charge layer (61), a multiplication layer (5), a second charge layer (62) and a transition layer which are arrayed in turn along the longitudinal direction, wherein the absorbing layer (8) is used for absorbing the target detecting light and converting photons of the target detecting light into photo-produced free carrier pairs; the first charge layer (61) is used for regulating and controlling the electric field distribution in a device; the multiplication layer (5) is used for causing the free carriers entering into the multiplication layer to trigger an avalanche effect and generate avalanche carrier pairs; and one type of carrier in the avalanche carrier pairs longitudinally drifts to one end of the avalanche photodetector through the transition layer (9). The avalanche photodetector can better regulate the capacitance of the avalanche photodetector and the transition time of the carriers and is beneficial to the increasing of the high frequency characteristics of the avalanche photodetector.

An imaging device is provided and includes: a photoelectric conversion layer that has a silicon crystal structure and generates signal charges upon incidence of light; a multiplication and accumulation layer that multiplies the signal charges by a phenomenon of avalanche electron multiplication; and a wiring substrate that reads the signal charges from the multiplication and accumulation layer and transmits the read signal charges. The photoelectric conversion layer includes: a first conductive impurity layer containing first impurities in an impurity concentration; an electron acceleration layer containing the first impurities in a lower impurity concentration than the first conductive impurity layer; and a second conductive impurity layer to which a voltage is applied, the second conductive impurity layer containing second impurities and disposed on a side opposite a light incidence side of the electron acceleration layer, and an insulating layer is disposed between the electron acceleration layer and the multiplication and accumulation layer.

The invention relates to an imaging arrangement for imaging an object. The imaging arrangement comprises: an X-ray source 5; an X-ray detector 6 arranged to receive X-rays transmitted through the object from the X-ray source 5, wherein the X-ray detector 6 comprises a gaseous-based edge-on direction sensitive line detector provided with an electron avalanche amplifier, and wherein the line detector is adapted to record a line image of radiation as transmitted through the object; and a support device 8 to which the X-ray source 5 and the X-ray detector 6 are attached so as to be arranged on opposite sides of the object, and wherein the support device 8 is arranged to rotate around the object and is also arranged to be movable in relation to the object. The invention also relates to a system comprising such imaging arrangement.

A single-photon avalanche detector is disclosed that is operable at wavelengths greater than 1000 nm and at operating speeds greater than 10 MHz. The single-photon avalanche detector comprises a thin-film resistor and avalanche photodiode that are monolithically integrated such that little or no additional capacitance is associated with the addition of the resistor.