Concepedia

Leakage current characteristics of offset-gate-structure polycrystalline-Silicon MOSFET's

S. Seki, Osamu Kogure, Bunjiro Tsujiyama

IEEE Electron Device Letters · 1987 · 83 citations · 8 references

Abstract

Leakage current characteristics of offset-gate-structure polycrystalline-silicon (poly-Si) MOSFET's are studied as a function of dopant concentration N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</inf> in offset-gate regions. Leakage current markedly decreases from 1 × 10 -9 to 2 × 10 -11 A at V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</inf> = 10 V as N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</inf> is varied from 1 × 10 18 to 1 × 10 17 cm -3 . A maximum ON/OFF current ratio of 10 8 is obtained at 1 × 10 17 cm -3 . Calculations based on a quasi-two-dimensional model indicate that the reduction of leakage current is attributable to a decrease of the maximum lateral electric field strength in the drain depletion region. An analysis of the leakage current characteristics in terms of carrier emission from grain-boundary traps implies that thermonic emission accompanied by thermally assisted tunneling could be the dominant mechanism in determining leakage current.