Non-stationary phase transitions in systems metallization of silicon structures

Abstract

We study the degradation of aluminum metallization under the thermal impact induced by rectangular current pulses with an amplitude of j < 8 × 10¹⁰ A/m² and a length of τ < 800 μs and experimentally investigate the thermal degradation of a metal film under the action of phase transformations, specifically, metal fusion and contact melting in a metal-semiconductor system during the passage of current pulses with a power above the critical value P_cr. It is demonstrated that the main mechanism of the fusion of a metallization stripe is related to heat release at the interface between the liquid and solid phases under the thermal impact. The velocities of liquid-phase propagation (10–50 m/s) along the metallization stripe have been determined in the experiment as a function of the electric power of the current pulse. The stresses in the silicon surface layers near the nonstationary heat source have been estimated. It is shown that current pulses with an electric power of ∼0.7P_cr induce the stresses sufficient for the formation of dislocations. The formation of dislocation half-loops in the silicon surface layers near the thermal impact source upon the passage of current pulses with a specified power has been observed.