PHOTOACOUSTIC TECHNIQUE FOR MONITORING THE THERMAL-PROPERTIES OF POROUS SILICON

The use of the photoacoustic technique to monitor the thermal properti es of materials that can be obtained only as parts of multicomponent s amples is illustrated by performing the thermal characterization of tw o porous materials: porous silicon obtained from n-type crystalline si licon through the spark process and that obtained through the electroc hemical etching method. This nonseparative, and hence nondestructive, approach makes use of an effective thermal diffusivity treatment based on the analogy between thermal and electrical resistances, in combina tion with simplified compositional models for the corresponding multic omponent systems. The thermal parameters obtained are in agreement wit h existent studies concerning the composition of these materials. This approach offers the possibility of performing the thermal characteriz ation of other porous semiconductors and analogous materials. (C) 1997 Society of Photo-Optical Instrumentation Engineers.