Influence of Termination Isolation Deep-Oxide Trenches on Short-Circuit Capability in Silicon-On-Insulator Lateral IGBT

Abstract

Termination isolation deep-oxide trenches (TITs) are inserted in the emitter side of silicon-on-insulator (SOI) lateral insulated gate bipolar transistor (LIGBT) for electrical isolation. TITs have unstudied effect on electrical characteristics of SOI-LIGBT. In this article, the influence of location and electrical potential of TITs on short-circuit characteristics is investigated. SOI-LIGBTs with different TITs are fabricated and measured, and then, detailed calibrated TCAD simulations are carried out to elucidate the influence of TITs. By adjusting the location of TITs, the electrical potential distribution in the emitter side is reshaped, and the electrical potential at the end of inversion channel ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{ch}}$ </tex-math></inline-formula> ) is lowered. A lower saturation current is achieved due to the reduced <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{ch}}$ </tex-math></inline-formula> . TITs with negative electrical potential can attract more holes in the short-circuit condition, which can suppress the activation of parasitic n-p-n transistor. Both reduced <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text{sat}}$ </tex-math></inline-formula> and suppressed latch up can significantly improve short-circuit withstanding time ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}_{\text{SC}}$ </tex-math></inline-formula> ). By optimizing location and electrical potential of TIT, SOI-LIGBT can achieve 69.1% increase in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}_{\text{SC}}$ </tex-math></inline-formula> at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{CE}} = 400$ </tex-math></inline-formula> V and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{GE}} = 15$ </tex-math></inline-formula> V without influencing other electrical characteristics.