51 results about "Surface photovoltage" patented technology

A method and apparatus for measuring damage of an ion implanted semiconductor wafer during semiconductor processing. The method includes the steps of conveying the wafer such that a surface of the wafer is substantially parallel to a surface photovoltage electrode of a head assembly during the semiconductor processing and exposing at least a portion of said wafer to light having a wavelength, and an intensity and modulating the light intensity at a predefined frequency. The method also includes the step of varying the frequency of the light intensity modulation and detecting the surface photovoltage in response to light modulated at the various frequencies using the surface photovoltage electrode. The method then calculates an electrical property of the wafer from the photovoltage induced at the surface of the wafer at each of the light intensity modulation frequencies.

A method of measuring a diffusion length of a minority carrier in a silicon wafer by a surface photovoltage method including irradiating the surface-treated silicon wafer with ultraviolet radiation in an oxygen-containing atmosphere, and measuring a diffusion length of a minority carrier in a silicon wafer by a surface photovoltage method.

There is provided a method for calculating a more accurate metal impurity concentration contained in a silicon wafer by correcting measured values with a calibration based on a dependent relationship of the minority carrier diffusion length with a period of time elapsing from the activation to the actual measurement, an electric resistivity, and a temperature if there is such a relationship, in the measurement of the metal impurity concentration by utilizing the surface photovoltage. In the calibration step, such dependent relationship may be obtained by utilizing the metal impurity concentration measured by methods of different principles and actually measured values are corrected in light of the dependent relationship in the measuring step such that the metal impurity concentration is measured more accurately.

Disclosed herein are various methods of determining characteristics of doped regions on device wafers, and a system for accomplishing same. In one illustrative embodiment, the method includes providing a device substrate comprising a plurality of masked areas, a plurality of unmasked areas, and at least one doped region formed in the substrate, determining a ratio between the unmasked areas and the masked areas for the device substrate, illuminating an area of the device substrate comprising the masked areas, the unmasked areas, and at least one doped region, and measuring an induced surface photovoltage of the device substrate while accounting for the ratio of the unmasked areas and the masked areas of the device substrate. In another illustrative embodiment, the method includes providing an SOI substrate comprised of an active layer, the active layer having a thickness, illuminating an area of the substrate using a light source having a wavelength that is sufficiently long such that an excited region created in the active layer due to the illumination does not extend beyond the thickness of the active layer, and measuring an induced surface photovoltage resulting from the illumination.

An apparatus and method for the real-time, in-line testing of semiconductor wafers during the manufacturing process. In one embodiment the apparatus includes a probe assembly within a semiconductor wafer processing line. As each wafer passes adjacent the probe assembly, a source of modulated light, within the probe assembly, having a predetermined wavelength and frequency of modulation, impinges upon the wafer. A sensor in the probe assembly measures the surface photovoltage induced by the modulated light. A computer then uses the induced surface photovoltage to determine various electrical characteristics of the wafer.

Disclosed herein are various methods of determining characteristics of doped regions on device wafers, and a system for accomplishing same. In one illustrative embodiment, the method includes providing a device substrate comprising a plurality of masked areas, a plurality of unmasked areas, and at least one doped region formed in the substrate, determining a ratio between the unmasked areas and the masked areas for the device substrate, illuminating an area of the device substrate comprising the masked areas, the unmasked areas, and at least one doped region, and measuring an induced surface photovoltage of the device substrate while accounting for the ratio of the unmasked areas and the masked areas of the device substrate. In another illustrative embodiment, the method includes providing an SOI substrate comprised of an active layer, the active layer having a thickness, illuminating an area of the substrate using a light source having a wavelength that is sufficiently long such that an excited region created in the active layer due to the illumination does not extend beyond the thickness of the active layer, and measuring an induced surface photovoltage resulting from the illumination.

A contactless sheet resistance measurement apparatus and method for measuring the sheet resistance of upper layer of ultra shallow p-n junction is disclosed. The apparatus comprises alternating light source optically coupled with first transparent and conducting electrode brought close to the wafer, the second electrode placed outside of illumination area. Using the measurement of the surface photovoltage signals inside illuminated area and outside this area and its phase shifts, linear SPV model describing its lateral distribution the sheet resistance and p-n junction conductance is determined.

The invention discloses an ultraviolet emitting material surface photovoltage spectrum testing device, which comprises a deuterium lamp light source, a chopper, a grating monochromator, an ultraviolet light-splitting optical fiber, an optical power meter, a photovoltage pool, a phase-locked amplifier and a computer, and is characterized in that the chopper is placed between the deuterium lamp light source and the grating monochromator; an incoming end of the ultraviolet light-splitting optical fiber is connected with a light outlet of the grating monochromator, a outgoing end of the ultraviolet light-splitting optical fiber is connected with the photovoltage pool and the optical power meter; a signal output end of the photovoltage pool is connected with a signal input end of the phase-locked amplifier; communication ports of the optical power meter and the phase-locked amplifier are connected with serial ports of the computer. According to the invention, the completely closed ultraviolet light-splitting optical fiber is adopted, so that interference imposed on surface photovoltage signals by external stray light can be effectively reduced; conductive glass in the photovoltage pool adopts deep-ultraviolet transparent conductive glass, so that ultraviolet emitting material surface photovoltage signals with high intensity and good stability can be acquired.

There is provided a silicon wafer surface defect evaluation method capable of readily detecting a region where small crystal defects exist, the evaluation method comprising: a rapid heat treatment step of a silicon wafer from a silicon single-crystal ingot in an atmosphere which can nitride silicon at a temperature elevating speed of 10 to 150° C. / second from a room temperature to temperatures between not lower than 1170° C. and less than a silicon melting point, holding the silicon wafer at the processing temperature for 1 to 120 seconds and then cooling the silicon wafer to the room temperature at a temperature lowering speed of 10 to 100° C. / second; and a step of using a surface photo voltage method to calculate a minority carrier diffusion length on the wafer surface, thereby detecting a region on the wafer surface in which small COP's which cannot be detected at least by a particle counter exist.

There is provided a silicon wafer surface defect evaluation method capable of readily detecting a region where small crystal defects exist. A silicon wafer surface defect evaluation method according to the present invention is characterized by comprising: a rapid heat treatment step of applying a heat treatment to a silicon wafer cut out from a silicon single-crystal ingot in an atmosphere which can nitride silicon at a temperature elevating speed of 10 to 150° C. / second from a room temperature to temperatures between not lower than 1170° C. and less than a silicon melting point, holding the silicon wafer at the processing temperature for 1 to 120 seconds and then cooling the silicon wafer to the room temperature at a temperature lowering speed of 10 to 100° C. / second; and a step of using a surface photo voltage method to calculate a minority carrier diffusion length on the wafer surface, thereby detecting a region on the wafer surface in which small COP's which cannot be detected at least by a particle counter exist.

The invention relates to a preparation method of a wide-spectrum and strong-absorption surface-photovoltage type photodetector, comprising the following steps of: adopting a titanium foil as a positive electrode, adopting platinum as a negative electrode, carrying out oxidation on the titanium foil and obtaining an amorphous TiO2 nano tube array; after treatment, obtaining a TiO2 nano tube array;putting the titanium foil in a high-temperature reaction kettle, then injecting aqueous solution of Na2S2O3 and Bi(NO3)3 into the sealed reaction kettle, carrying out heat treatment and obtaining a Bi2S3-TiO2 nano tube array; covering FTO on the surface of the Bi2S3-TiO2 nano tube array, leading out an electrode; leading out an electrode on the titanium foil without generating the Bi2S3-TiO2 nanotube array; and packaging the contact edges of the FTO, the titanium foil and the Bi2S3-TiO2 nano tube array to obtain the photodetector. The method is low in energy consumption and simple in processand equipment; and the prepared photodetector is applicable to a large spectrum range, is suitable for spectrum analysis, can also be used as photoelectric devices such as a photosensitive switch andthe like and has wide application prospect.

An apparatus and method for the real-time, in-line testing of semiconductor wafers during the manufacturing process. In one embodiment the apparatus includes a probe assembly within a semiconductor wafer processing line. As each wafer passes adjacent the probe assembly, a source of modulated light, within the probe assembly, having a predetermined wavelength and frequency of modulation, impinges upon the wafer. A sensor in the probe assembly measures the surface photovoltage induced by the modulated light. A computer then uses the induced surface photovoltage to determine various electrical characteristics of the wafer.

The invention relates to the field of material chemistry and especially relates to the field of photocatalytic materials, and particularly provides a preparation method for significantly enhancing surface photo-voltage signal of BiOCl. The method includes the steps of: 1) dissolving bismuth nitrate in glacial acetic acid and adding glucan 20000; 2) dropwise adding 10 ml of a KCl solution to the bismuth nitrate-glacial acetic acid-glucan solution to obtain a precipitate, wherein the mole number of KCl is equal to that of the bismuth nitrate; 3) hydrothermally treating the precipitate in a hydrothermal reaction kettle and naturally cooling a product to room temperature; and 4) washing the produced powder with deionized water and ethanol, dispersing the powder in ethanol, and drying the mixture to obtain a sample. With assistance of the glucan 20000, the surface photo-voltage signal of the BiOCl sample is significantly enhanced in the range of 300-500. The method has simple operations, employs easy-to-obtained raw materials, is easy to carry out and is safe and reliable.

The invention relates to an atomic force microscope and surface photovoltage spectrum combination method for measuring a surface photovoltage spectrum of a semiconductor surface micro region to solve the problem that the surface photovoltage spectrum has no spatial resolving power. An atomic force microscope and a spectrometer are combined by using a chopper for modulating a variable wavelength signal and combining the surface potential variation with a lock-in amplifier, and the surface photovoltage spectrum of the semiconductor surface micro region and a phase angle resolution spectrogram can be given.

The present invention discloses an apparatus and method for real-time, on-line testing of semiconductor wafers during the manufacturing process. In one embodiment, an apparatus includes a detector assembly within a semiconductor wafer processing line. As each wafer travels into proximity with the detector assembly, a modulated light source within the detector assembly having a predetermined wavelength and modulation frequency illuminates the wafer. Sensors in the detector assembly measure the surface photovoltage induced by the modulated light. A computer then uses the sensed surface photovoltage to determine various electrical properties of the wafer.

The invention uses energy complementary relation of surface acoustooptic effect of conductor and semiconductor material and surface photovoltaic effect, combines results of optical acoustic spectrum and surface photovoltage spectrum, supplies a optical acoustic and photovoltaic detecting method of surface electron-phonon of conductor and semiconductor material. Using measuring method, can directly discuss; interaction of electron-phonon on surface and interface of conductor and semiconductor, and effective effective channel of radiationless de excitation course happened on surface and interface. The invention has properties of noncontiguous, nonpreprocessing, quick testing and high sensitivity, whose sensitivity can reach photovoltage spectrum multiply to the power. Atoms / cu cm which is usually higher than some standard energy spectrum or spectrum such as multiply PS or Auger electron energy spectrum several order of magnitude. The apparatus is simple and convenient, whose operation can be under room temperature and acoustooptic signal created by exciton in radiationless de excitation course can be observed, mostly important, it can supply information of electron-phonon on material surface and interface.

The present invention is to provide a method for measuring resistivity of a semiconductor wafer by the use of an AC-SPV method even though the wafer is left in a depletion state or a weak inversion state. The present invention is the method for measuring resistivity of a semiconductor wafer by the use of a surface photo voltage method, and comprises the steps of: (a) measuring a surface photo voltage value in both regions of a low frequency region in which a constant surface photo voltage value is obtained irrespective of a frequency of incident light on a semiconductor wafer to be measured and in a high frequency region in which the surface photo voltage value inversely proportional to the frequency of the incident light is obtained and calculating a cut-off frequency fc from the obtained measured value; (b) calculating a depletion layer width Wd from capacitance Cdp calculated from the surface photo voltage value in the high frequency region; (c) calculating majority carrier conductance gmj from the cut-off frequency fc and the capacitance Cdp; and (d) calculating surface potential Us and Fermi potential UF from the cut-off frequency fc, the capacitance Cdp, the depletion layer width Wd, and the majority carrier conductance gmj.

A contactless sheet resistance measurement apparatus and method for measuring the sheet resistance of upper layer of ultra shallow p-n junction is disclosed. The apparatus comprises alternating light source optically coupled with first transparent and conducting electrode brought close to the wafer, the second electrode placed outside of illumination area. Using the measurement of the surface photovoltage signals inside illuminated area and outside this area and its phase shifts, linear SPV model describing its lateral distribution the sheet resistance and p-n junction conductance is determined.

The invention relates to the field of preparation of a chemical material, particularly to the field of a photocatalysis material, more particularly to a preparation method of graphite-like carbon nitride (g-C3N4) with an enhanced surface photovoltaic signal. The method comprises: taking urea as a raw material, performing calcination at 550 DEG C for 3h through a current semi-closed method to obtain g-C3N4; performing hydro-thermal treatment to the prepared g-C3N4 with the assistance of an ionic liquid or a surfactant, and performing natural cooling to the room temperature; washing obtained powder with deionized water and then with alcohol for 1-2 times; taking the powder out and dispersing the obtained powder in alcohol; and drying the obtained powder at 60-80 DEG C to obtain g-C3N4. The graphite-like carbon nitride (g-C3N4) material treated with the assistance of an ionic liquid or a surfactant has an enhanced surface photovoltaic signal, and is simple in preparation method, available in raw materials, and low in cost.

The invention relates to the field of material chemistry, in particular to the field of photocatalytic materials, and particularly relates to a method for improving a BiOCl surface photovoltage signal. The method comprises the following steps: dispersing black phosphorus powder in a certain volume of glacial acetic acid, and carrying out ultrasonic dispersion; adding bismuth nitrate, dissolving the bismuth nitrate in the black phosphorus-glacial acetic acid suspension solution, and dropwise adding a KCl solution (the mole number of KCl is equal to the mole number of bismuth nitrate) into the bismuth nitrate-glacial acetic acid-black phosphorus suspension solution; and transferring the generated suspension system into a hydrothermal reaction kettle for hydrothermal reaction, after the hydrothermal reaction is naturally cooled to room temperature, washing the precipitate with deionized water and alcohol, taking out the precipitate, and carrying out vacuum drying to obtain a sample. A surface photovoltage signal of a BiOCl sample prepared under the assistance of a proper amount of black phosphorus is obviously enhanced in a range of 300-400nm. The method is easy to operate, easy to implement, safe and reliable.

A method and apparatus for thickness measurement of an active layer of a silicon-on-insulator material comprising a layered structure of silicon film, a buried oxide layer and a silicon substrate. In one embodiment, the method comprises the steps of directing a low intensity light of an energy greater than the silicon band-gap on the silicon film, the energy of light sufficient to be substantially absorbed within the silicon film such that the error from the substrate excitation is small compared to the small signal calibration of the apparatus; modifying the surface potential with the chemical treatment, electrical bias or corona, measuring surface photovoltage of the silicon film; and calculating the thickness of the silicon film in response to a non-contact photovoltage measurement of the semiconductor layered structure.

The invention discloses a surface photovoltage method based semiconductor material parameter testing device and testing method. The testing device comprises a casing, a cantilever, a measuring probe and a sample bench, wherein the measuring probe is internally provided with an infrared laser and a sensing electrode slice; a pulse light source driver is positioned inside the casing; a semiconductor material sample to be tested is arranged on the sampling bench; the measuring probe is right over the sample to be tested; the sensing electrode slice is connected with a charge amplifier through a coaxial cable wire; and the infrared laser is connected with the pulse light source driver through a two-core shield wire. The testing method is as follows: the pulse light emitted by the infrared laser is vertically irradiated on the sample, the sensing electrode slice receives the static charge generated by the weak photovoltage on the surface of the sample for transmitting to the input end of the charge amplifier, and a liquid crystal display screen displays the conductive type and resistivity / sheet resistance values of the sample to be tested after the static charge is processed by a signal processing circuit. The testing device provided by the invention has the advantages of small volume, light weight, small power consumption and low cost.

The invention discloses a surface photovoltage signal detection method for enhancing spatial resolution. The method comprises the following steps of: pretreating a sample, and starting a Kelvin forcemicroscope and a lock-in amplifier; installing a conductive probe plated with specific metals (gold, silver, copper and other metals with a plasma resonance effect); fixing the sample and adjusting scanning parameters; and starting a chopper, and recording photovoltage signals for enhancing spatial resolution of the sample. According to the testing method disclosed by the invention, the scanning probe plated with the specific metal has a local surface plasma resonance effect, so that the light field intensity of a sample region below the probe tip can be enhanced, and the surface photovoltagesignals can be remarkably enhanced. The enhanced surface photovoltage signals are stable and good in repeatability, and an idea is provided for detecting weak surface photovoltage signals.

Provided is a method for evaluating defects in a wafer. The method for evaluating the wafer defects includes preparing a wafer sample, forming an oxidation layer on the wafer sample, measuring a diffusion distance of a minority carrier using a surface photovoltage (SPV), and determining results of a contamination degree.

A metal contamination immediate monitoring method of a semiconductor wafer is provided to include: performing a rapid thermal oxidation process on the wafer; and performing surface photo-voltage measurement on the wafer after the rapid thermal oxidation process.