| 摘要 |
PURPOSE:To measure a deep level of a semiconductor by arranging the attenuation time constant of a radiation light and the temperature of a specimen in coordinate relation wherein an excitation light or a bias for excitation at the specimen in the pulse form is being applied. CONSTITUTION:In some cases, the radiation lights generated by illuminating a semiconductor crystal with a pulse-shaped excitation light would be attenuated. The reason therefor is that electrons or positive holes are thermally emitted from a deep level to the conduction hand or valence electron band to suppress illumination at its level. When determining a dependence on the temperature T at its time constant, the ionization energy ET of the deep level can be obtained from 1/tau=Aexp(-ET/kT). Controlling 5 the temperature of a specimen 4 at a fixed temperature, illuminating a continuous laser beam 11 as a pulse light 12 via an audio-optic modulator 2, converging 6 radiation lights 13, and passing through a spectroscope 7, a monochromatic light 14 is detected 8 to convert into a corresponding electric signal, and then it is wave-analyzed at 9 to determine tau. A level can be specified by obtaining ET by varying T, thereby, a cause can be directly and definitely analyzed. |
