Residual strains in GaAs (100) wafers, sliced from single-crystal ingots grown by the horizontal Bridgman technique, have for the first time been characterized by measuring strain-induced birefringence with a high-sensitivity computer-controlled infrared polariscope. The residual strain components: \S(r)-S(t)\, \S(yy)-S(zz)\, and 2\S(yz)\ are quantitatively characterized from the measured birefringence values. It was found that the maximum strain value was as low as about 5 X 10(-6) and the corresponding stress value was about 3 X 10(5) N/m2. Also there was no strong correlation between the measured residual strain and etch pit density distributions. The origin of residual strains is discussed in conjunction with the correlation between the residual strain and dislocation distributions.
