A simple, effective and flexible microcomputer-based deep level transient spectroscopy (DLTS) system for the measurement of deep levels in semiconductors is developed and implemented.
By using assembly language program with micro-computer, excitation pulse frequency, pulse width and amplitude as well as emission rate windows are controllable and variable, and the temperature variation is also checked by the microcomputer. Furthermore, by using BASIC program with personal computer, least square curve fitting method is used to find Arrhenius plot and calculate activation energy. The trap density, activation energy and capture cross section of a gold doped pnp transistor(model no. 2N2422) are measured by the system in order to test the performance of the system.
In addition, the DLTS spectra, Arrhenius plots and C-V plots can be plotted by a line printer and displayed in CRT monitor after one thermal scan.