Electrical measurements in silicon under shock-wave compression

The electrical behavior of p-type silicon in the (111) orientation was studied under shock stresses from 8 to 160 kbar. Positive electrical signals are induced in the crystals during passage of elastic shock waves. Maximum signal amplitude was detected below the Hugoniot elastic limit (55 kbar). Resistance-vs-stress measurements were made when the polarization signal was zero, i.e., no elastic waves were in the crystals. The resistance becomes very small near the elastic limit, indicating that a metallic state is reached. The relative resistance, R/Ro, then increases significantly at 133 kbar where a phase transition is indicated.