Channel Strain in Advanced Complementary Metal–Oxide–Semiconductor Field Effect Transistors Measured Using Nano-Beam Electron Diffraction

概要

論文の詳細を見る
Using high-precision nano-beam electron diffraction (NBD), we clarified the influences of stress liner and the stress of shallow trench isolation on channel strain in advanced metal–oxide–semiconductor field effect transistors (MOSFETs). For systematic strain measurements, we improved the precision of NBD by observing large reciprocal lattice vectors under appropriate diffraction conditions. The absolute value of the channel strain increases by stress liner as gate length decreases, although the drive current increase due to stress liner saturates at a shorter channel length. The normal strain in the gate length direction is inversely proportional to the distance from the gate electrode to the shallow trench isolation (STI). Furthermore, the relationship between measured channel strain induced by STI and drive current change was shown. The drive current of n- and p-MOSFET changes about 5% with $2\times 10^{-3}$ channel strain variation. This result suggests that reducing the shallow trench isolation stress is effective for controlling the drive current change, depending on the active region layout. We conclude that the experimental measurement of channel strain is necessary for device and circuit design.
2008-04-25