843 results about "Dark current" patented technology

An image sensor using a back-illuminated photodiode and a manufacturing method thereof are provided. According to the present invention, since a surface of the back-illuminated photodiode can be stably treated, the back-illuminated photodiode can be formed to have a low dark current, a constant sensitivity of blue light for all photodiodes, and high sensitivity. In addition, it is possible to manufacture an image sensor with high density by employing a three dimensional structure in which a photodiode and a logic circuit are separately formed on different substrates.

A MOS or CMOS based active pixel sensor designed for operation with zero or close to zero potential across the pixel photodiodes to minimize or eliminate dark current. In this preferred embodiment, the voltage potential across the pixel photodiode structures is maintained constant and close to zero, preferably less than 1.0 volts. This preferred embodiment enables the photodiode to be operated at a constant bias condition during the charge detection cycle. In preferred embodiments the pixel photodiodes are produced with a continuous pin or nip photodiode layer laid down over pixel electrodes of the sensor. In other preferred embodiments the pixel photodiode structures are produced beside and physically isolated from the regions where CMOS circuits are formed. In some of these preferred embodiments the isolated pixel photodiode structures are comprised of crystalline germanium deposited in cavities in a silicon substrate. This embodiment can be adapted especially for imaging at short wave infrared frequencies. Preferred embodiments are adapted for correlated double sampling.

The invention relates to an ultraviolet detector, in particular to a visible-blind ultraviolet detector based on a Beta-Ga2O3/SiC heterojunction thin film and a fabrication method of the visible-blind ultraviolet detector. According to the fabrication method, a layer of Beta-Ga2O3 thin film is deposited on an n-type 6H-SiC substrate by a laser molecular beam epitaxial technique, and then a layer of Ti/Au thin film is deposited on the n-type 6H-SiC substrate and the Beta-Ga2O3 thin film through a mask by a radio frequency magnetron sputtering to be used as an electrode. The fabricated visible-blind ultraviolet detector has the advantages of stable performance, response sensitivity, small dark current and high potential application; and moreover, the fabrication method has the characteristics of high process controllability, simplicity in operation, high universality, restorability of repeated test and the like, and has great application prospect.

The 3D CT imaging method for large view field comprises: (1) taking first single-circular orbit cone-beam CT scanning to obtain the first digital ray projection image sequence; (2) removing the platform vertical the main ray with some distance to take the second CT scanning and obtain the second image sequence; (3) correcting former two images for dark current and inconsistency; (4) recording distance from ray source to detector, former moved distance and detector level channel number; (5) with the projection rearrangement algorithm in this invention, rearranging former two images into self-contained quasi-parallel image sequence; (6) with the quasi-parallel ray reconstructing algorithm in this invention, reconstructing the 3D CT image. This invention can enlarge the view area more than 3 times with high efficiency.

The invention discloses a multi-quantum-well structure used in photoelectron device, wherein the thickness of a potential well layer near N type semiconductor layer is larger than that of the potential well near P type semiconductor layer. The invention also discloses a manufacturing method of the multi-quantum-well structure, including that Ga barrier layer N and InxGa potential well layer N are alternately grown on the N type semiconductor layer of the photoelectron device by adopting MOCVD technology, wherein the growth time of the InxGa1-x potential well layer N near the N type semiconductor layer is 50-200s, and the growth time of the InxGa1-x potential well layer N near the P type semiconductor layer is 0.5-1 time that of the potential well layer near the N type semiconductor layer. The multi-quantum-well structure of the invention can improve the internal quantum efficiency of the photoelectron device, improves reverse voltage and antistatic property, and reduces halfwidth of the luminous spectrum peak to improve luminous purity; and the structure can reduce dark current to improve the sensitivity of a detector when being applied in the detector.

The present invention provides a method for calculating APD breakdown voltage and a circuit thereof. The method comprises the following steps: 1, adding reserve voltage Vapd on an APD in a condition without light; 2, dark current (Idark) generated by the APD flows into a trans-resistance amplifier (3) after passing through a current mirror (2); 3, reversely calculating the dark current (Idark) through output voltage (Vo) of the trans-resistance amplifier (3); and 4, determining whether the dark current (Idark) of the APD is equal to 10 [Mu]A or not, if the dark current (Idark) of the APD is equal to 10 [Mu]A, allowing the APD at present to be the breakdown voltage of the APD, or else, repeatedly setting the Vapd, and returning back to the step 3. The method for calculating APD breakdown voltage and the circuit thereof can accurately find the Vbr of the APD so as to find reasonable reverse direction work voltage Vapd, are good in precision, efficiency and consistence, improve the yield rate of an optical module, improve production efficiency and reduce production cost.

An imaging system may include processing circuitry, a lens, and an array of pixels including image sensor pixels and temperature sensor pixels. The image sensor pixels may generate image pixel values in response to image light received through the lens. The temperature sensor pixels may generate thermal estimate signals based on the temperature of the pixel array. The image sensor pixels and temperature sensor pixels may generate dark current. As the temperature of the pixel array increases, the image sensor pixels and temperatures sensor pixels may generate increased dark current. Temperature sensor pixels may generate more dark current than image sensor pixels. Dark current generated by the temperature sensor pixels may be used to generate dark current compensation values that may compensate for the dark current generated by the image sensor pixels.

A InGaAs/InP PIN photoelectric detector relating to a semiconductor component has the structure of double hetergeneous material in four layer of i-In0.53 Ga 0.47As photosensitive layer/i-InP buffer layer/N+-Inp substrate. There is P+ zinc diffusion layer which is close to i-In 0.53 Ga0.47 As photosensitive layer but not reach the photosensitive layer at the top layer. It is prepared by the following steps, growing a passivation film of aluminium oxide on the epitaxial sheet and carrying out open-type zinc diffusion by using zinc as a diffusion source, depositing high quality film of aluminiumoxide on InP material by directly using evapouration to reduce dark current, and raising the signal to noise ratio. The film obtained can be used in passivation film of InP material.

The invention discloses a zinc oxide nano-ultraviolet light sensor and a preparation method thereof. The sensor at least comprises zinc oxide nano-rods horizontally arranged and conductive film electrodes, and the preparation method is as follows: a photoresist mask of an inserted electrode is made on a substrate by using traditional photoetching technology, a passivation layer without affinity for ZnO is deposited on a seed layer with affinity for ZnO deposited on the substrate, and the ZnO nano-bars are grown by using hydro-thermal method that is a low-temperature and stable method having high repetitiveness; owing to competition for space when the nano-bars are grown, most nano-bars are grown parallel to the substrate and are connected in the middle of a channel so as to form the ZnO nano-ultraviolet light sensor, thereby having smaller dark current (about 3nA per 1V bias). The invention has simple technology and low cost, and can prepare large-scale ZnO nano-sensor array; and the once in place technology also guarantees the performances of apparatus.

The invention relates to a method for preparing a direct current (DC) magnetron sputtering AZO/SiO2/p-SiSIS heterojunction photoelectric device, and belongs to the technical field of methods for preparing silicon-based heterojunction photoelectric devices. By growth of an ultrathin SiO2 layer through low-temperature thermal oxidation, DC magnetron sputtering of an AZO emitter, antireflection and collection of an electrode film, a novel AZO/SiO2/p-SiSIS ultraviolet-visible-near-infrared broad-spectrum heterojunction photoelectric device is successfully prepared. An I/V curve of the prepared AZO/SiO2/p-SiSIS heterojunction has good rectification characterisitic and very low reverse dark current, so a good heterojunction diode is formed between AZO and p-Si. Under the condition of AM 1.5 illumination, the open-circuit voltage VOC is 230mV, the photoelectric conversion efficiency eta is 0.025 percent, and the photovoltaic effect is obvious. By combining different characteristics of a wide band gap of the AZO and a relatively narrow band gap of a Si material for mutual complementation, the SIS heterojunction can be developed into a low-cost solar cell, and also can become an excellent-performance ultraviolet-visible-near-infrared enhanced broad-spectrum photoelectric detector.

The invention discloses a diffusion technology for reducing dark current of a metallurgical silicon solar battery, which includes the steps of firstly, carrying out concentrated phosphorus diffusion at the low temperature: feeding from a high-concentration phosphorus source for diffusion at the low temperature so as to form high-concentration phosphor doping; secondly, performing phosphorus gettering for a long time at the high temperature: releasing impurities such as deposited impurities, displacement impurities or other impurity complexes of iron, carbon, boron, oxygen and the like into interstitial impurities at the high temperature, so that the interstitial impurities quickly release into a phosphorosilicate glass layer with high solid solubility, high-temperature phosphorus gettering is completed, and the minority carrier lifetime of a body is prolonged; and thirdly, propelling at the lower temperature: at the lower temperature, propelling the junction depth, adjusting to square resistance meeting technological requirements, and lowering the solid solubility of the impurities in a surface concentrated area along with the temperature, so that the interstitial impurities turn to the deposited impurities, the complex impurities and the like. A metallurgical crystal silicon wafer is diffused by means of the diffusion technology, so that the dark current of the solar battery can be effectively reduced, and the conversion efficiency of the solar battery is improved.