Systematic Study of the Dopant-Dependent Properties of Electrically Programmable Fuses With Silicided Poly-Si Links Through a Series of I– V Measurements

Electrically programmable/writable fuses (e-fuses) with a Ni-silicided polycrystalline silicon narrow link and fabricated with four doping conditions were studied using two successive I-V measurements. The initial I-V sweeps can change e-fuses into targeted programmed states and display all of the programming processes where the currents change by many orders of magnitude. The second set of I-V curves can show stability and conduction in the programmed states for both bias polarities. Through the series of I-V measurements, the two-step programming with moderate blowing conditions could be reproduced and studied systematically. The programming processes of incompletely programmed states, before complete programming (CP), were found to be strongly dependent on the dopant conditions. The origin of the dopant dependency was considered within a simple electrical equivalent circuit model. At least two or three programmed states were identified among the completely programmed states in terms of the characteristic spreads of the final resistance and conduction behavior. The most distinctive currents after CP are similar to those in varistors. The stability of every programmed state is strongly dependent on the dopant conditions.