Current-voltage-measurement temperature characteristics depending on the barrier-forming contact metal thickness in Au/Cu/n-Si/Au–Sb/Ni rectifying contacts

We experimentally have introduced the current–voltage-temperature (I–V-T) characteristics of the Au/n-type Si (D1), Au/Cu/n-Si (D2), Au/Cu(4 nm)/n-Si (D3) and Au/Cu(2 nm)/n-Si (D4) Schottky-barrier diodes (SBDs) in the temperature range of 40–320 K with the step of 10 K. The copper Schottky contact (SC) dots for the D2, D3 and D4 SBDs have the thickness of 100 nm, 4 nm and 2 nm, respectively. The top Au contact has been used as a shield to prevent oxidation of the copper SC metal. The Schottky barrier height (SBH) Φb0 values of 0.61 eV, 0.66 eV and 0.69 eV, and the ideality factor values of 1.04, 1.04 and 1.02 for the D2, D3 and D4 SBDs have been obtained at 300 K, respectively. The SBH value has increased with decreasing Cu thin film thickness. An average series resistance Rs value of 10.6 Ω has been obtained for the Au/Cu/n-Si diodes at 300 K. The obtained Rs and the ideality factor values are almost independent of the SC metal thickness. In the SBH vs temperature plots, the SBH value in the D3 and D4 diodes with 2 nm and 4 nm metal thickness almost remained unchanged from 320 K to 120 K, and in the D2 SBD from 320 K to 160 K. Therefore, it can be said from these results that the quality of the SBDs has increased with decrease in Cu Schottky film thickness.