Optimizing the Breakdown Voltage and Specific on-Resistance of SOI LDMOS with an Inverted T-Shaped Oxide Trench and Highly Doped P/N Columns

In this paper, a novel lateral double-diffused MOSFET(LDMOS) based on silicon-on-insulator (SOl) technology with an inverted T-shaped oxide trench and highly doped P/<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$N$</tex> columns (ITTPN) is proposed. The new structure features an inverted T-shaped oxide trench and highly doped P/N columns. The P columns at the left of the trench help deplete the drift region. In addition, it will also cause the drift region to achieve a high doping concentration, thus reducing the specific on-resistance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(R_{\text{on},\text{sp}})$</tex>. Furthermore, a lower resistance path for the carriers is formed owing to the highly doped N column, which can further reduce <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\text{on},\text{sp}}$</tex>. The P/N columns and the inverted T-shaped oxide trench can modulate the electric field in the drift region, enhancing the breakdown voltage (BV). Based on the simulation, compared with the conventional trench SOl LDMOS (Con-T LDMOS), the ITTPN LDMOS eventually reaches a BV of 194 V and a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\text{on},\text{sp}}$</tex> of 2.76 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{m}\Omega\cdot \text{cm}^{2}$</tex>. which are improved by 56% and 73%, respectively; at the same time, the figure of merit (FOM) is 13.64 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{MW}/\text{cm}^{2}$</tex>, which is an improvement of 803%.