Evidence That Two Tightly Coupled Mechanisms Are Responsible for Negative Bias Temperature Instability in Oxynitride MOSFETs

• Published in: IEEE transactions on electron devices Vol. 56; no. 5; pp. 1056 - 1062
• Main Authors: Grasser, T., Kaczer, B.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-05-2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bias; Charge carrier processes; Dangling bonds; Defects; Degradation; E^{\prime} centers; Electronics; Exact sciences and technology; hole trapping; Instability; Interface states; negative bias temperature instability (NBTI); Niobium base alloys; oxide charges; reaction-diffusiontheory; Recovery; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Stability; Stress; Stress measurement; Stresses; Temperature measurement; Transistors; Trapping; Voltage measurement; Thermal stress; Negative bias temperature instability; Interface state; MOSFET; reaction-diffusion theory; E' centers; oxide charges; Electric stress; PMOS technology; negative bias temperature instability (NBTI); hole trapping; Dangling bonds; Charge carrier trapping; interface states; MOS transistor; Reliability; Dangling bond; Defect formation; Damaging
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2009.2015160

Negative bias temperature instability (NBTI) is a serious reliability concern for pMOS transistors. Although discovered more than 40 years ago, the phenomenon remains highly controversial in both experimental and theoretical terms. A considerable number of recent publications suggest that NBTI is caused by the following two independent mechanisms: 1) generation of defects close to the silicon/silicon dioxide interface and 2) hole trapping in the oxide. We have performed stress and recovery experiments at different temperatures and voltages that, quite surprisingly, reveal that all data can be scaled onto a single universal curve during stress, recovery, and restress. This suggests that in our samples, NBTI is caused by either a single dominant mechanism, which is more complicated than previously anticipated, or that the previously suggested mechanisms, i.e., hole trapping and defect creation, are actually tightly coupled.