Photoluminescence assessment of B, P, and Al in Si wafers: The problem of sample heating by a laser beam

A line shape analysis of free-exciton low-temperature (4.2 K) photoluminescence spectra is applied to monitor the heating of Si samples due to an exciting Ar+-ion laser beam. The heating is studied in dependence on the laser beam intensity. The temperature as a line shape fitting parameter can be established within ±0.15 K. Continuous minor increase of the sample temperature is observed up to an intensity of ∼200 W cm−2, followed by an abrupt temperature jump up to tens of K. Possible inaccuracies, resulting from the heating, in photoluminescent quantitative determination of boron, phosphorus, and aluminum are discussed.