Improved Hot-Carrier Reliability of an Ultralow R ON,sp SOI-LDMOS by Linearly Doped Technology for Automotive Application

In this work, an ultralow specific ON-resistance ( ${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ ) silicon-on-insulator lateral double diffusion metal-oxide-semiconductor (SOI-LDMOS) applied in automotive circuits has been fabricated based on the $0.18~\mu \text{m}$ process technology with 16.5 $\text{m}\Omega \cdot $ 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 ${R}_{ \mathrm{\scriptscriptstyle ON}}$ 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 ${R}_{ \mathrm{\scriptscriptstyle ON}}$ 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 ${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ about 17.5 $\text{m}\Omega \cdot $ mm2.