Platinum silicide Schottky barrier infrared photodetectors with a grating: optical response and backbias-dependent polarization sensitivity

Platinum silicide Schottky barrier detectors are widely used for infrared applications in the 3-5 /spl mu/m wavelength region. The uniformity of the metal deposition along with the compatibility of the fabrication process with standard CMOS technology makes PtSi highly suited for large and high resolution focal plane arrays. To improve the quantum efficiency we have fabricated PtSi Schottky diodes on p-Si with various dry-etched lamellar gratings. The grating periods were 3 /spl mu/m, 4 /spl mu/m and 5 /spl mu/m, and the grating amplitudes were chosen between 300 nm and 1100 nm. The grating structure influences the optical properties of the diode and the absorption in the PtSi layer depends on the polarization of the incoming radiation. For TE-polarized light the E-field vector is parallel to the grating grooves, for the TM-polarization it is perpendicular.