Optimization and Experiments of Lateral Semi-Superjunction Device Based on Normalized Current-Carrying Capability

Abstract

A lateral double diffused metal oxide semiconductor transistor with the semi-superjunction (semi-SJ LDMOS) is optimized based on the normalized current-carrying capability (CC) and experimentally realized in this letter. The device is fabricated based on an optimized equivalent substrate and the semi-SJ is introduced near the source. The semi-SJ increases the local doping concentration in the N regions meanwhile reduces the current path area and carrier mobility, resulting in the variation of CCs before and after the introduction of the semi-SJ. The normalized CC factor η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> is proposed to evaluate this variation, with which the minimum specific on-resistance R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,sp</sub> is predicted by the condition of η <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> = 1. The experiments of the semi-SJ LDMOS exhibit a minimum R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,sp</sub> of 25.5 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> under a breakdown voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> of 464.3 V. This represents a reduction in R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,sp</sub> by 37.7% when compared with the theoretical R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,sp</sub> of triple RESURF devices.