Electronic Materials

The objective of this project is to develop a real-time, non-contact laser ultrasonic technology for detecting embedded voids (microns) and assessing bond integrity of joining materials at micro-level. This technology will be implemented to support process development and production of Silicon Carbide (SiC) semiconductor and devices. This new breed of SiC has been identified as the material of the future because of its superior properties to withstand harsh performance environments where traditional silicon and gallium arsenide (the semiconductor used in nearly all of today's electronics) cannot function. An example includes flameout detectors on uncooled aircraft engine operating in excess of 600 degrees C and beyond. Non of the traditional process control technologies is suitable nor efficient enough to support the fabrication of these SiC structures. Simpex Technologies' proposed technology consists of two independent lasers. The pulse laser is used as the source while the continuous wave laser is used as the detector. Simply, our technique represents an automation of the classical `tap test' in which the surface is struck in some fashion and an experienced listener determines the flaw and adhesion from the sound generated. This technique is much improved from the traditional contact type techniques. The object need not be contacted, the excitation is much gentler than that required in a contact test, and the whole approach lends itself to automation.