Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Norwegian University of Life Sciences

Elénore Letty

Jordi Veirman

Wilfried Favre

Espen Olsen

Torbjørn Mehl

Lisa Kvalbein

Ingunn Burud

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

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Elénore Letty