Transistor Mismatch Properties in Deep-Submicrometer CMOS Technologies

Abstract

Transistor mismatch data and analysis from poly/SiON and high-k/metal-gate (HKMG) bulk CMOS technologies are presented. It is found that the traditional mismatch figure of merit from the Pelgrom plot (A <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VT</sub> ) continuously scales down as technology advances. Furthermore, the A <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VT</sub> values for both nFET and pFET in the HKMG technology are significantly reduced from poly/SiON technologies. By normalizing the mismatch data against electrical oxide thickness (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">INV</sub> ) , threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ), and effective work function, a direct comparison of the mismatch data from various technologies is made. The differences in nFET and pFET mismatch behaviors in both poly/SiON and HKMG technologies are discussed in detail. Correlation between transistor V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> mismatch and flicker noise variation is observed in both poly/SiON and HKMG technologies. Finally, it is quantitatively demonstrated that effective work function variation does not generate significant V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> variability in the present HKMG technology.