A Simple and Low-Cost Personal Computer-Based Automatic Deep-Level Transient Spectroscopy System for Semiconductor Devices Analysis

A simple, low-cost, and flexible, automatic, deep-level transient spectroscopy (DLTS) system with an Apple II microcomputer for semiconductor devices analysis is described. By using an interactive Basic software program, all the instrument parameters including sampling aperture locations, temperatures, excitation pulse frequency, width and amplitude can be controlled automatically. The transient signals are also averaged by the software program. Furthermore, a linear square regression method is used to calculate the activation energy. The trap density, capture cross section, activation energy of n-type Sidoped GaAs, grown by molecular beam epitaxy (MBE) system, was measured and compared with conventional boxcar DLTS sytem. In addition, the DLTS signal spectra and the Arrhenius plots can be plotted by a line printer and displayed on a CRT monitor during one thermal scan. An IEEE-488 interface bus was designed for communication between personal computers and instruments. This configuration provides the advantages of ease of operation and rapid set up, especially for the purpose of data acquisition and processing.