Adsorption of Au on InSb(100): A Scanning Tunneling Microscopy Study

We report a novel low temperature (LT — 77 K) deposition process at high vacuum to make reliable, high-barrier height Schottky contacts to ft«InF. The electrical and interface properties of the metal//?-XnP were investigated by current-voltage {!-¥) and capacitance-voltage (C - V) techniques, photoreflectance (PR), and Raman spectroscopies. For the LT diode made on 8n-doped w-InP, the leakage current density ₀, and barrier height < f_Bwere found to be L4x 1G~ A/cm and 0.83 eV, respectively. Undoped InP gave J_Q — 6.7X 10” ^A/cmand (f)_B= Q.96 eV. This indicated a reduction of more than six orders of magnitude in J₀, corresponding to a 0.4-0.5 eV increase in _Bcompared with the metal?-InP diodes made at room temperature (RT = 300 K). The Schottky metal property was studied as a function of deposition temperature and film thickness. Very good agreement was obtained between the electrical and the optical measurements. The high barrier height and low leakage current can be attributed to the dual modification of metal and InP near the interface as well as less disruption of the InP surface.