A non-destructive optical characterisation technique is used for the invest
igation of Mercury Cadmium Telluride (HgCdTe) photovoltaic devices. The tec
hnique uses a scanning laser microscope to obtain Laser Beam Induced Curren
t (LBIC) data from which it may be possible to extract information such as
junction depth, array uniformity, and other material and device parameters.
LBIC has been previously used only as a qualitative technique, but in this
work the procedure is being developed into a quantitative tool. At present
the only junction depth profiling techniques are destructive, while array
uniformity can only be examined after bonding to readout circuits. In this
paper we present both theoretical and experimental results which show that
LBIC can be employed as a quantitative tool for device characterisation. Th
e primary measure of performance of IR detectors is the zero bias dynamic r
esistance junction area product, R(0)A. LBIC measurements indicate that the
peak LBIC signal varies by a factor of similar or equal to 2 for long wave
length infrared photodiodes for which the R(0)A varies between 70 Ohm cm(2)
(acceptable for operation and the lower bound of typical values) and 8 Ohm
cm(2) (unacceptable and typical for poor quality diodes). (C) 2000 Elsevie
r Science Ltd. All rights reserved.