Transistor Mismatch Properties in Deep-Submicrometer CMOS Technologies

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_VT) continuously scales down as technology advances. Furthermore, the A_VT 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_INV) , threshold voltage (V_TH), 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_TH 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_TH variability in the present HKMG technology.