Electrical Characterization of Phosphorus Doped Ion Beam Synthesised CoSi₂/Si Schottky Barrier Diodes.

Abstract

The current/voltage characteristics of ion beam synthesised CoSi₂/Si (n - type) Schottky barrier diodes implanted with phosphorus to doses between 5 × 10¹² and 2 × 10¹³ ions cm⁻²are examined after annealing at temperatures in the range 400°–1000°C. For each dose of implanted phosphorus, the effective barrier height of the CoSi₂/Si interface is successively reduced as the anneal temperature increases. The results of Secondary Ion Mass Spectroscopy (SIMS) analysis indicate that these changes are due to an increase in the space charge density at the interface. For lower annealing temperatures the increase in space charge density is attributed to activation of the phosphorus in the tail of the dopant distribution which extends across the CoSi₂/Si interface. For higher annealing temperatures larger increases in the space charge density are attributed to a modified dopant distribution resulting from phosphorus diffusion and activation at the interface. For doses of 1 × 10¹⁴ P⁺ cm⁻²and 2×10¹⁵P⁺cm², ohrnie characteristics are seen after annealing at temperatures of 1000°C and 500°C respectively.