ON-state reliability of amorphous-silicon antifuses

Abstract

The ON state of metal-to-metal amorphous-silicon antifuses suffers from two reliability concerns: switch-off and dc-stress failure. The switch-off current and dc-stress lifetime are strongly dependent on the temperature of the conducting filament and hence, on the programming current and ambient temperature. Numerical simulations of the filament temperature in the ON state were carried out to explain the experimental characteristics obtained in this work such as the dependence of the switch off and dc-stress failures on ambient temperature, stress current, and programming current. The temperature in the conducting filament is found to increase as the square of the stress current. The temperature and power dissipation at switch off are found to be independent of the programming current. The temperature at switch off is determined to be approximately 1500 °C. The ON-state device lifetime decreases exponentially with increasing stress current and ambient temperature. Numerical simulations of the temperature in the ON state successfully explain the experimentally observed increase in switch-off currents with programming current and the exponential decrease in device lifetime with increasing programming currents, stress currents, and ambient temperature.

A Thermal Model for the Initiation of Programming in Metal‐to‐Metal Amorphous‐Silicon Antifuses

“…The temperature in the antifuse under a given set of programming conditions is obtained by solving the heat equation. Then, the maximum temperature at the edges of the via at a given applied voltage is given by [4] where T amb is the ambient temperature, the thermal conductivity of amorphous silicon, a the radius of the via, i a constant, and J n (x) the Bessel function of the first kind of order n. The constant i is determined to be the root of the transcendental equation J 0 (a) ϭ 0 [5] From Fig. 1, the above equation can be reduced to T max ϭ 1.29206 ϫ 10 Ϫ6 V af exp(1.98945V af ) ϩ T amb [6] This steady-state temperature value is calculated for various values of the applied voltage.…”

“…[1][2][3] We have previously reported on the energy considerations during the growth of a molten filament in metalto-metal amorphous-silicon antifuses, 4 and on the ON-state reliability of amorphous-silicon antifuses. 5 In this paper, we present a thermal model for the initiation of programming in these antifuses.The antifuses studied in this work are located in the via between two metal layers. The bottom metal electrode is Al-Si-Cu/TiW and the top metal electrode is Ti/TiW/Al-Si-Cu.…”

“…[1][2][3] We have previously reported on the energy considerations during the growth of a molten filament in metalto-metal amorphous-silicon antifuses, 4 and on the ON-state reliability of amorphous-silicon antifuses. 5 In this paper, we present a thermal model for the initiation of programming in these antifuses.…”

The Effect of the Dielectric Layer with Surface Plasma Treatment on Characteristics of Amorphous Silicon Antifuse

“…Most of the existing metal-to-metal antifuses show very good off-state reliability; however, their on-state reliability is still an area of concern [19]. It was found that an amorphous silicon antifuse, once programmed, can switch back to the off-state during later operation.…”

On-State Resistance Instability of Programmed Antifuse Cells during Read Operation

“…It can induce the read disturb: the R ON increase of programmed antifuse cells to an off-state resistance (R OFF ) level during read operation. In the case of metal-insulator-metal (MIM) antifuse cells, read disturb problems have already been reported [5,6]. On the other hand, in the case of standard CMOS antifuse cells, few research results on read disturb problems have been reported yet.…”