Room-temperature irradiation of silicon with 2 MeV electrons can create many defects that give rise to optical absorption lines. This paper describes a simple procedure for calculating the strengths of the more important absorption features and the concentrations of the corresponding defect centres as functions of the radiation dose and of the carbon and oxygen concentrations in the silicon. The following absorption features and centres are considered: the 969 meV line (twocarbon-atom centre), the 865 cm" line (C + O centre), the 1 0 2 0 cm" line (C + 0 + self-interstitial), the 835 cm" line (vacancy + 0 'A centre'), the 1.7 p m band (di-vacancy) and the 488 meV line (C + 0 +vacancy centre).

Since nitrided oxides improve gate leakage at the expense of NBTI, one must optimize nitrogen concentration in oxinitride samples for reliable performance and reduced power dissipation. Here, we analyze wide range of NBTI stress data to develop a predictive model for gate leakage and first selfconsistent model for field acceleration within R-D framework. This model anticipates a novel design diagram for co-optimization of leakage and NBTI for arbitrary nitrogen concentration and effective oxide thickness.1. Introduction Since nitrided oxides (SiON) improve gate leakage (J G ) [1-6] at the expense of NBTI performance (∆V T ) [7,8], one must necessarily optimize N 2 concentration (%N) in gate-oxides for high-performance ICs. Despite its importance, however, a quantitative analysis of leakage/NBTI trade-off (as a function of %N), has never been reported and the question "Is cooptimization of NBTI/leakage possible at any %N?" has never been answered. In this paper, we simultaneously measure gate leakage and delay-free NBTI over broad range of stress-fields, stress-temperatures and %N, model gate leakage current (J G ) and NBTI degradation within a theoretically consistent framework (hole-assisted thermal generation of interface traps) of field-dependent R-D model, and conclude that although there is no optimum %N for NBTI/leakage, the reduction in J G at NBTI-limited %N (~15-25%, depending on failure criterion) can be significant and would reduce power dissipation without affecting NBTI-margin.2. Gate Leakage Comprehensive simulation [9] (which includes the effects of multi-subband electron/hole quantization, poly-depletion, etc.) of the measured J G -V G for both N-and PMOS (Fig. 1) was done to extract the model parameters as a function of %N (Fig. 2). We assume that any variation in the spatial-profile of nitrogen results only in second-order correction to calculated J G . Contrary to popular belief [2-6, 10], the oxide parameters do not scale linearly with %N. All the parameters have approximately a quadratic fit with %N. Here, effective oxide thickness (EOT) is obtained from simulation of CV, and physical thickness (T PHY ) and %N are determined by XPS [11]. These %N-dependent parameters are used to calculate J G (N,EOT) for arbitrary %N and EOT, as shown in Fig. 10b. -1.0 -0.5 0.0

Recently, 1/f and random telegraph noise (RTN) studies have been used to infer information about bulk dielectric defects' spatial and energetic distributions. These analyses rely on a noise framework which involves charge exchange between the inversion layer and the bulk dielectric defects via elastic tunneling. In this study, we extracted the characteristic capture and emission time constants from RTN in highly scaled nMOSFETs and showed that they are inconsistent with the elastic tunneling picture dictated by the physical thickness of the gate dielectric (1.4 nm). Consequently, our results suggest that an alternative model is required and that a large body of the recent RTN and 1/f noise defect profiling literature very likely needs to be re-interpreted.

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We utilize low-frequency noise measurements to examine the sub-threshold voltage (sub-V TH ) operation of highly scaled devices. We find that the sub-V TH low-frequency noise is dominated by random telegraph noise (RTN). The RTN is exacerbated both by channel dimension scaling and reducing the gate overdrive into the sub-V TH regime. These large RTN fluctuations greatly impact circuit variability and represent a troubling obstacle that must be solved if sub-V TH operation is to become a viable solution for low-power applications.