Improved Hot-Carrier Reliability of an Ultralow <i>R</i> <sub>ON,sp</sub> SOI-LDMOS by Linearly Doped Technology for Automotive Application
Li Lu, Jiaojing Bian, Shulang Ma, Yongsheng Liu, Yixin Dai, Zhihan Zhu, Siyang Liu, Weifeng Sun, Feng Lin, Chaoqi Xu, Penglong Xu
Abstract
In this work, an ultralow specific ON-resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ </tex-math></inline-formula> ) silicon-on-insulator lateral double diffusion metal-oxide-semiconductor (SOI-LDMOS) applied in automotive circuits has been fabricated based on the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18~\mu \text{m}$ </tex-math></inline-formula> process technology with 16.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega \cdot $ </tex-math></inline-formula> mm2 which leads about 30% than that of reported studies. However, the poor hot carrier reliability of the SOI-LDMOS cannot fulfill the automotive circuits. To solve it, a new device has been proposed with linearly doped technology based on the discussions on the inner mechanisms of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{\scriptscriptstyle ON}}$ </tex-math></inline-formula> degradation. Thanks to the linear doping concentration in lateral and vertical directions near the damage points (poly-gate edge and bird’s beak), the impact ionization and vertical electric field have been weakened evidently. As a result, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{\scriptscriptstyle ON}}$ </tex-math></inline-formula> degradation of the proposed device (Device A) has been improved effectively and decreased from 11% to lower 1% when stressing 10000 s under the hot carrier stress. Meanwhile, the static electrical parameters of the Device A are still in an acceptable changes with OFF-state breakdown voltage (BVOFF) about 55 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">${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ </tex-math></inline-formula> about 17.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega \cdot $ </tex-math></inline-formula> mm2.