EL2 distribution measuring method null of gallium arsenide semiconductor ue -

摘要

PURPOSE:To obtain distribution of EL2 through non-contact method in order to improve wafer quality by irradiating a GaAs semiconductor wafer with electromagnetic wave while irradiating it with the light having the energy higher than the forbidden bandwidth and obtaining distribution of EL2 from distribution of transmitting and reflecting amounts of light measured. CONSTITUTION:Measurement of a part having particular energy level for a GaAs semiconductor wafer, namely the region generally called EL2 is carried out as described below. Namely, the surface of GaAs wafer 1 is irradiated with the laser beam emitted from the laser diode 2 and the rear side of wafer 1 is irradiated with the microwave 5a generated from the microwave generator 3 through a circulator 4 and a waveguide 6. The microwave 5b which is not absorbed by the wafer 1 and is reflected is caused to pass through the waveguide 6 and the circulator 4. Moreover, such microwave 5b is detected by a detector 7 and is then amplified by an amplifier 8. Distributions of transmitting amount and reflecting amount of wafer 1 are obtained thus obtained and it is compared with the distribution obtianed by ordinary non-contact measuring method, thus realizing adequate measurement even during the manufacturing process.