Physics and Characterization of Various Hot-Carrier Degradation Modes in LDMOS by Using a Three-Region Charge-Pumping Technique

Abstract

Degradation of lateral diffused MOS transistors in various hot-carrier stress modes is investigated. A novel three-region charge-pumping technique is proposed to characterize interface trap <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(N_ it)$</tex> and bulk oxide charge <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q_ ox$</tex> creation in the channel and in the drift regions separately. The growth rates of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$N_ it$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q_ ox$</tex> are extracted from the proposed method. A two-dimensional numerical device simulation is performed to gain insight into device degradation characteristics in different stress conditions. This paper shows that a maximum <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$I_g$</tex> stress causes the largest drain current and subthreshold slope degradation because of both <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$N_ it$</tex> generation in the channel and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q_ ox$</tex> creation in the bird's beak region. The impact of oxide trap property and location on device electrical characteristics is analyzed from measurement and simulation.