Theory and characterization of random defect formation and its implication in variability of nanoscale transistors
30 Sep 2011 | Papers | Contributor(s): Ahmad Ehteshamul Islam
Over the last 50 years, carrier transport has been the central research topic in the semiconductor area. The outcome was a dramatic improvement in the performance of a transistor, which is one of the basic building blocks in almost all the modern electronic devices. However, nanoscale dimensions of current transistor following Moore's law have shifted the spotlight from carrier transport towards the reliability and variability constraints. Modern transistors operate at a high electric field. …
Essential Aspects of Negative Bias Temperature Instability (NBTI)
01 May 2011 | Online Presentations | Contributor(s): Ahmad Ehteshamul Islam, Souvik Mahapatra, Muhammad Alam
We develop a comprehensive theoretical framework for explaining the key and characteristic experimental signatures of NBTI. The framework is based on an uncorrelated dynamics of interface-defect creation/annihilation described by Reaction-Diffusion (R-D) theory and hole trapping/detrapping into/out-of oxide defects based on a generalized Shockley-Read-Hall model. The proposed theory can consistently explain the long-term stress-phase power-law time exponent, stress/relaxation-phase temperature …
Universality of NBTI-Induced Interface Trap Generation and Its Impact on ID Degradation in Strained/ Unstrained PMOS Transistors
23 Dec 2008 | Online Presentations | Contributor(s): Ahmad Ehteshamul Islam, Muhammad A. Alam
Despite extensive use of strained technology, it is still unclear whether NBTI-induced NIT generation in strained transistors is substantially different from that of unstrained ones. Here, we present a comprehensive theory for NIT generation in strained/unstrained transistors and show its universality over a wide range of strain. We further propose that an appropriately designed/optimized transistor might reduce/eliminate NBTI being a concern for CMOS scaling.
Brick Nanotechnology Center for ...
On the Resolution of Ultra-fast NBTI Measurements and Reaction-Diffusion Theory
30 Dec 2009 | Online Presentations | Contributor(s): Ahmad Ehteshamul Islam, Souvik Mahapatra, Muhammad A. Alam
Reaction-Diffusion (R-D) theory, well-known to successfully explain most features of NBTI stress, is perceived to fail in explaining NBTI recovery. Several efforts have been made to understand differences between NBTI relaxation measured using ultra-fast methods and that predicted by R-D theory. Many alternative theories have also been proposed to explain ultra-fast NBTI relaxation, although their ability in predicting features of NBTI stress remains questionable. In this work, a ...
Mobility Variation Due to Interface Trap Generation in Plasma Oxynitrided PMOS Devices
30 Jun 2008 | Online Presentations | Contributor(s): Ahmad Ehteshamul Islam, Souvik Mahapatra, Muhammad A. Alam
Mobility degradation due to generation of interface
traps, Δµeff(NIT), is a well-known phenomenon that has been
theoretically interpreted by several mobility models. Based on
these analysis, there is a general perception that Δµeff(NIT) is
relatively insignificant (compared to Δµeff due to ionized
impurity) and as such can be safely ignored for performance and
reliability analysis. Here, we investigate the importance of
considering Δµeff(NIT) for reliability analysis by analyzing a ...