Dual-Layer Proton Irradiation for Creating Thermally-Stable High-Resistivity Region in Si CMOS Substrate

This paper presents dual-layer proton irradiation profile to improve the thermal stability of high-resistivity substrate formed by low-fluence proton irradiation. Dual-layer irradiation uses targeted irradiation to the Si-SiO
2
interface to reduce the fluence required for preventing the formation of conduction layer after annealing. Thermal stability of effective substrate resistivity is evaluated indirectly through inductor Q-factor measurement before and after annealing at 260°C for 1-minute. With the same total fluence of
$4\times 10^{14}\text{cm}^{-2}$
, measurement result shows dual-layer irradiation profile can suppress post-anneal Q-factor degradation from 17% in conventional proton irradiation to 1%. The required active devices margin from irradiated area is reduced by 26% to
$22\mu \mathrm{m}$
, compared to
$30\mu \mathrm{m}$
in conventional irradiation.