Characterization of prototype BTeV silicon pixel sensors before and after irradiation

We report on measurements performed on silicon pixel sensor prototypes exposed to a 200-MeV proton beam at the Indiana University Cyclotron Facility. The sensors are of n⁺/n/p⁺ type with multiguard-ring structures on the p⁺-side and p-stop electrode isolation on the n⁺-side. Electrical characterization of the devices was performed before and after irradiation up to a proton fluence of 4×10¹⁴ p/cm². We tested pixel sensors fabricated from normal and oxygen-enriched silicon wafers and with two different p-stop isolation layouts: common p-stop and individual p-stop.