Commissariat a L'energie Atomique Et Aux Energies Alternatives

Norwegian University of Life Sciences

Jordi Veirman

Sébastien Dubois

Nicolas Enjalbert

Wilfried Favre

Elénore Letty

Pierre Gidon

Jean-Paul Garandet

Florent Tanay

Espen Olsen

Torbjørn Mehl

Lisa Kvalbein

Ingunn Burud

Julie Stendera

A method for treating a stack includes a substrate of n-doped crystalline silicon and a passivation layer of hydrogenated amorphous silicon disposed on a face of the substrate, the method including exposing the stack to electromagnetic radiation during a treatment period (t) less than or equal to 12 s, the electromagnetic radiation having an irradiance (E) greater than or equal to 200 kW/m.

Method for treating a stack obtained during the manufacture of a heterojunction photovoltaic cell

A method for determining the thermal donor concentration of a test sample made of a semiconductor material, includes providing a reference sample made of the same semiconductor material and having a known thermal donor concentration; measuring a photoluminescence signal of the reference sample for a photon energy comprised between 0.65 eV and 0.8 eV, the photoluminescence signal of the reference sample exhibiting an intensity peak in a photon energy range of 0.65 eV to 0.8 eV; determining, from the photoluminescence signal, an experimental relationship between the thermal donor concentration and a parameter representative of the intensity peak; measuring a photoluminescence signal of the test sample for at least one photon energy comprised between 0.65 eV and 0.8 eV; determining from the photoluminescence signal a specific value of the parameter; and determining the thermal donor concentration from the specific value of the parameter by using the experimental relationship.

Method for determining the thermal donor concentration of a semiconductor sample

An experimental method for validating a thermal history of a semiconductor ingot obtained by simulation of a crystallization process, includes a) measuring the concentration of interstitial oxygen in a portion of the semiconductor ingot; b) calculating a theoretical value of the concentration of thermal donors formed during the crystallization process, from the measurement of the concentration of interstitial oxygen and from the thermal history in the portion of the semiconductor ingot; c) measuring an experimental value of the concentration of thermal donors in the portion of the semiconductor ingot; and d) comparing the theoretical and experimental values of the concentration of thermal donors.

Method for validating the thermal history of a semiconductor ingot

A Czochralski-type method for sorting wafers obtained by cutting a single-crystal silicon ingot, the method being implemented when the wafers are in an as-cut state or in a shaped-surface state. The method includes a) measuring the majority free charge carrier concentration in an area of each wafer; calculating the thermal donor concentration in the area of each wafer, on the basis of the majority free charge carrier concentration; calculating the charge carrier lifetime limited by the thermal donors in the area of each wafer, on the basis of the thermal donor concentration; determining a bulk lifetime value for the charge carriers in each wafer on the basis of the lifetime limited by the thermal donors; comparing the bulk lifetime value or a normalised bulk lifetime value with a threshold value; and discarding the wafer when the bulk lifetime value or the normalised bulk lifetime value is lower than the threshold value.

Method for sorting silicon wafers according to their bulk lifetime

A method for determining the original position of a wafer in an ingot made from semiconductor material comprises the following steps: measuring the interstitial oxygen concentration in an area of the wafer; measuring the concentration of thermal donors formed in said area of the wafer during a previous solidification of the ingot; determining the effective time of a thermal donor formation anneal undergone by the wafer when solidification of the ingot took place, from the thermal donor concentration and the interstitial oxygen concentration; and determining the original position of the wafer in the ingot from the effective time.

Method for locating a wafer in the ingot of same

A method for calibrating a furnace enabling a semiconductor material to be subjected to a first thermal donor formation annealing that includes a temperature rise, a first temperature plateau and a temperature drop of the furnace, the method to including providing a calibration piece of the semiconductor material; determining the interstitial oxygen concentration of the piece; subjecting the piece to a second thermal donor formation annealing in the furnace, the second annealing including rise and drop in temperature of the furnace identical to those of the first annealing and a second plateau at the set temperature for a set time; determining the concentration of thermal donors formed in the piece during the second annealing; determining an equivalent annealing time at the set temperature, corresponding at least to the rise and drop in temperature of the furnace, from the interstitial oxygen concentration, the thermal donor concentration of the piece and the set time.

Method for calibrating an annealing furnace used to form thermal donors

A method for forming a silicon ingot includes the following steps: providing a silicon ingot of variable electrical resistivity and containing interstitial oxygen, determining the interstitial oxygen concentration in different areas of the silicon ingot, calculating the concentration of thermal donors to be created in the different areas to reach a target value of the electrical resistivity, and subjecting the different areas of the silicon ingot to annealing so as to form the thermal donors. The annealing temperature in each area is determined from the thermal donor and interstitial oxygen concentrations of the area and from a predefined annealing time.

Method for forming a doped silicon ingot of uniform resistivity

A restoration device of at least one silicon-based photovoltaic solar cell is provided with a support of the cell and a charge carriers generator configured to generate charge carriers in the photovoltaic solar cell. The device is further provided with a tank designed to be filled by a liquid, and the support is configured to place the photovoltaic solar cell in the liquid.

Device and method for restoring silicon-based photovoltaic solar cells

The restoration device of least one silicon-based photovoltaic solar cell includes a support of the cell, a heat source configured to heat the photovoltaic solar cell, and unit for generating charge carriers in the cell. To better accelerate the restoration kinetics of the solar cell, the device includes an ultrasonic transducer designed to generate ultrasonic waves propagating in the photovoltaic solar cell.

Device and method for restoring silicon-based solar cells using an ultrasound transducer

A method for determining the oxygen concentration of a sample made from p-type semiconductor material includes a thermal treatment step to form the thermal donors, a measuring step of the charge carrier concentration of the sample at a temperature between 0 K and 100 K, a step of determining the thermal donor concentration of the sample from the charge carrier concentration and the temperature of the sample, and a step of determining the interstitial oxygen concentration from the thermal donor concentration.

Determination of the interstitial oxygen concentration in a semiconductor sample

A method for determining the interstitial oxygen concentration of a sample made from a p-doped semiconductor material includes a step of heat treatment of the sample in order to form thermal donors, determining the duration of the heat treatment required to obtain a compensated semiconductor material, determining the thermal donors concentration in the sample of compensated semiconductor material, from the charge carriers concentration, and determining the oxygen concentration from the thermal donors of and the duration of the heat treatment.

Method for determining interstitial oxygen concentration

A method for determining the oxygen concentration of a sample made of a semiconductor material includes a heat treatment step of the sample to form thermal donors, the measurement of the resistivity in an area of the sample, the determination of the thermal donor concentration from a relation expressing the charge carrier mobility according to an ionized dopant impurity concentration, by adding to the dopant impurity concentration four times the thermal donor concentration, and from the measured resistivity value. The method finally includes determining the oxygen concentration from the thermal donor concentration.

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Poisy, France

Jordi Veirman