| 摘要 |
PURPOSE:To clarify whether deep impurity level is electron trap or hole trap by using the measured result of the light transient response of hole current (voltage). CONSTITUTION:A constant voltage electric field E and vertical magnetic field B are applied to a semiconductor crystal 1 and the occupancy rate of the electrons at capture level in the crystal or holes is changed by irradiating pulse light and a generated transient response signal is measured 4 at the hole terminal 3 in the crystal and is plotted by changing crystal temperature. When carriers are electrons, signals in solid lines are obtained, and in the case of holes, signals in dashed lines are obtained and the sum of these lines is measured. Observation is made for temperature T and a difference, sigmaxy(t1)-sigmaxy(t2) in electric conductivity is plotted. A positive signal is obtained at the temperature T1 representing the trap resulting in electron current and a negative signal is obtained at the temperature T2 representing the trap resulting in hole current and information for obtaining the energy level of each trap can be obtained. Furthermore, whether the electron trap or hole trap can be decided from the code of a signal peak. |
