Reducing the effective barrier height of a PtSi Schottky diode by a p+ doping spike using pulsed laser doping

Abstract

The structure of PtSi/p+/p-Si fabricated by chemical vapour doping has been investigated for reduction of the Schottky barrier height. The interface structure and photoelectric properties of PtSi/p+/p-Si thin film structure have been studied. The results from AES profile analysis show that doped boron moves with the PtSi/Si interface during silicide growth. Concomitantly, the boron at the PtSi/Si interface out-diffuses to the Pt–PtSi interface. Finally, the boron piles up at the surface. It has been considered that the redistribution of the dopant boron is due to the solubility of the dopant in the silicide. The Schottky barrier height of PtSi/p+/p-Si is 0.13 eV (for cutoff wavelength 9.5 µm). That is lower than the 0.19 eV value of PtSi/p-Si (for cutoff wavelength 6.5 µm). Since the Schottky barrier height is lowered, the cutoff wavelength can be extended. Due to the Fowler dependence, the detector's quantum efficiency can be improved.