Zh. Chen et al., PHOTOTHERMAL RATE-WINDOW SPECTROMETRY FOR NONCONTACT BULK LIFETIME MEASUREMENTS IN SEMICONDUCTORS, Journal of applied physics, 73(10), 1993, pp. 5043-5048
A new noncontact technique for the determination of excess carrier lif
etimes in semiconductors is presented. The technique employs a square
laser pulse (hv > E(g)) and measures the infrared photothermal radiome
tric response of the sample. By applying the photothermal rate-window
concept, the excess photoexcited carrier bulk lifetime was measured wi
th optimal signal-to-noise (S/N) ratio and simple, unambiguous interpr
etation from the maximum position of the rate-window signal. The techn
ique has been applied to Au-, Fe-, and Cr-doped Czochralski silicon cr
ystals. The experimental results from boxcar and lock-in rate-window m
ethods were found to agree very well. The results are further mostly i
n agreement with those from the noncontact laser/microwave detection m
ethod.