Radiation Hardened SOI LDMOS With Dual P-Type Layers Shielding Irradiation Charge Field

In this paper, a novel radiation hardened SOI LDMOS with dual P-type layers is proposed. Based on irradiation charge field modulation, two P-type layers are introduced at the surface and bottom in N-drift region for suppressing shifts of both 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">$(R_{\textrm {on,sp}})$ </tex-math></inline-formula> and breakdown voltage (BV). Irradiation charge field is shielded by the P-type layers at low drain voltage and electron behavior in the bulk is protected against the modulation, resulting in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\textrm {on,sp}}$ </tex-math></inline-formula> shifting less significantly. Besides, net charge density in drift region is reduced by the P-type layers, and then surface electric field is weakened at source side, resulting in a non-monotonic shift in BV. A low net charge density with high donor doping concentration in P-N-P drift region is pursued instead of charge balance required in traditional design. Simulated optimized results show that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\textrm {on,sp}}$ </tex-math></inline-formula> shifts only 11.4% at TID <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${=} 300$ </tex-math></inline-formula>krad(Si).