Impact of Deuterium and Fluorine Incorporation on Weibull Distribution of Dielectric Breakdown in Gate Dielectrics

Abstract

TDDB (Time-Dependent Dielectric Breakdown) is still serious in the context of efforts to realize highly reliable ULSI. In particular, the statistical distribution of TDDB is essentially important from the viewpoint of determining the lifetime of the devices. In this work, we focus on the effect of deuterium (D) and fluorine (F) incorporation into gate oxides on TDDB statistics. These elements can terminate (passivate) dangling bonds of silicon or oxygen in SiO2 and its interface. As a result, stress-induced leakage current (SILC) is suppressed by deuterium incorporation, and consequently, Weibull distribution of Tbd shifts to long lifetime maintaining Weibull slope. Furthermore, Weibull slope monotonously increases with increasing fluorine dosage. On the basis of experimental results, the suppression of probability of Si-H bond breakage and the structural relaxation of SiO2 network invoke the improvement of Weibull distribution of Tbd.