Steve S. Chiang

Dielectric based antifuse for logic and memory ICs

The authors describe a programmable low-impedance circuit element (PLICE), which is a dielectric-based antifuse for use in both logic and memory ICs. The antifuse element offers significant size and performance improvement compared to other programmable cells. A simple thermal model has been developed to predict the antifuse resistance. Each antifuse occupies an area of 1.5- mu m/sup 2/ using 1.2- mu m technology. It can be programmed within 1 ms and has a tight resistance distribution centered around 500 Omega . The reliability of both the programmed and unprogrammed states is demonstrated to be better than 40 years. The antifuse was used in the design of the first family of desktop-configurable channeled gate arrays and a 64 K PROM (programmable read-only memory) device.<<ETX>>

An electro-thermal model for metal-oxide-metal antifuses

In this paper, a complete electro-thermal analysis is presented for the metal-oxide-metal antifuses. The application of the Wiedemann-Franz Law and the thin film effect on thermal and electrical conductivities of metal films were also discussed. Several key parameters for tungsten-oxide-tungsten antifuse were extracted. The reaction temperature between tungsten and oxide was estimated to be around 1300/spl deg/C. The core resistivity was found to be around 250 /spl mu//spl Omega//spl middot/cm. This model can be readily extended to the other metal-dielectric-metal systems. >

Oxide-nitride-oxide antifuse reliability

Compact, low-resistance oxide-nitride-oxide (ONO) antifuses are studied for time-dependent dielectric breakdown (TDDB), program disturb, programmed antifuse resistance stability, and effective screen. ONO antifuses are superior to oxide antifuses. No ONO antifuse failures were observed in 1.8 million accelerated burn-in device-hours accumulated on 1108 product units. This is in agreement with the 1/E field acceleration model.<<ETX>>

Metal-to-metal antifuses with very thin silicon dioxide films

Antifuse samples with very thin insulating oxide were fabricated using a technique of two-step PECVD oxide deposition. Dielectric strength as high as 13 MV/cm was obtained for our samples. Defect density and uniformity have been improved in this way. The on-state resistance of the programmed antifuses shows a stronger dependence on the oxide thickness when it was programmed at the lower current than when it was programmed at the higher current.<<ETX>>

Characteristic voltage of programmed metal-to-metal antifuses

The characteristic voltage V/sub f/ of different programmed metal-to-metal antifuses was measured and found to be nearly independent of the electrode materials. An electrothermal model, used previously to predict programmed silicon-electrode antifuse resistance, was extended to explain the above phenomenon. The metal-to-metal antifuse resistance vs. the programming current is governed by the Wiedeman-Franz Law.<<ETX>>

Reliable metal-to-metal oxide antifuses

This paper presents a new high performance, reliable metal-to-metal antifuse. The problem of switch-off in the programmed antifuses is avoided by using metals with low thermal conductivity and thin oxide.<<ETX>>