A note on TiN/Si (1 0 0) contacts

Abstract

The contact properties of TiN on p- and n-type Si (1 0 0) obtained by magnetron reactive sputtering were investigated. Schottky diode characteristics were observed on p-type Si (1 0 0) as determined by forward current–voltage ( I– V) measurements, but on n-type Si (1 0 0) the reverse I– V relation has shown a nonsymmetrical character. The zero-bias barrier heights evaluated by I– V on both type diodes were in the range of ∼0.60–0.64 V within the range of a few mVs, not more than ∼±(10–30) mV from each other. Incorporation of the effect of the series resistance in the I– V analysis resulted in a significant reduction in the magnitude of the ideality factor of the TiN/p-type specimen. Almost no change has occurred in the barrier height values. The contradictory reports on the TiN/n-type Si (1 0 0) diode characteristics in earlier works have been explained in terms of surface passivation of Si by the HF cleaning solution. It was stated in these reports that following annealing at 673 K the diodes have shown rectifying behavior. It has been speculated, that the nonsymmetrical nature of the TiN/n-Si (1 0 0) showing an intermediate behavior between Ohmic and rectifying behavior is a result of the specimen being exposed to a temperature lower than 673 K during sputtering where no complete depassivation took place. In order to obtain a rectifying behavior of TiN on both n-type and p-type Si surface passivation has to be eliminated.