ON-STATE RELIABILITY OF AMORPHOUS-SILICON ANTIFUSES

The ON state of metal-to-metal amorphous-silicon antifuses suffers fro m two reliability concerns: switch-off and dc-stress failure. The swit ch-off current and dc-stress lifetime are strongly dependent on the te mperature of the conducting filament and hence, on the programming cur rent and ambient temperature. Numerical simulations of the filament te mperature in the ON state were carried out to explain the experimental characteristics obtained in this work such as the dependence of the s witch off and dc-stress failures on ambient temperature, stress curren t, and programming current. The temperature in the conducting filament is found to increase as the square of the stress current. The tempera ture and power dissipation at switch off are found to be independent o f the programming current. The temperature at switch off is determined to be approximately 1500 degrees C. The ON-state device lifetime decr eases exponentially with increasing stress current and ambient tempera ture. Numerical simulations of the temperature in the ON state success fully explain the experimentally observed increase in switch-off curre nts with programming current and the exponential decrease in device li fetime with increasing programming currents, stress currents, and ambi ent temperature. (C) 1998 American Institute of Physics. [S0021-8979(9 8)01123-2].