瞬态C-V法测量AlGaAs:Si中DX中心的电离能(英文)

Determination of Thermal lonization Energy of DX Centers in AIGaAs:Si by Constant Temperature Transient C-V Measurement

The thermal ionization energy ET of DX centers in AlxGa1-xAs and its dependence with the value of x and the pressure are very important for estab- lishing the model of DX centers. The conventional DLTS and Hall methods used to DX center measurement have some ambiguities in theoretical analysis and experiments and the values of ET determined are different with those methods. The new constant temperature transient C-V measurement is based on the fact that at low temperature both electron capture and emission rates of DX centers are very slow. During the transient C-V measurement, change; of bias voltages and capacitance measurements are completed in a time duration much shorter than the electron capture and emission time constants, therefore the electrons occupied on the DX centers are considered to be frozen. The density of DX centers, the distribution profile of electrons on DX centers in the depletion region of a Schottky diode at a constant reverse bias, and the density of free electrons in conduction band in the bulk and their temperature dependence have been measured.