Thermal stability of Pt Schottky contacts to 4H–SiC

Abstract

Depth profiles by x-ray photoelectron spectroscopy have been used in conjunction with currentvoltage measurements to study the thermal stability of a 50-nm-thick Pt contact to n-4H-SiC substrate. A reaction between the Pt and the SiC substrate is observed at temperatures of 600°C and above. Annealing below that temperature improves the ideality and the uniformity of the Schottky characteristics, while annealing above this temperature degrades the electrical performance and uniformity. Thermodynamic stability is not reached even after annealing for 1 h at 900°C. A local improvement of the characteristics at 800°C is correlated with the formation of a second graphite film in the Pt-SiC reaction.

Platinum-enhanced graphitisation in sandwich structures of silicon carbide and borosilicate glass

“…First nanoanalytical measurements via ELNES in correspondence with quantum-chemical calculations give hints to a preference of the silicide Pt 2 Si [30]. This would also be in agreement with the observation that the presence of C in the Pt-Si-C system (as in our case) favours the formation of metal-rich silicides [31].…”

Observations of conduction-band structure of4H- and6H−SiC

“…The first current threshold is observed at ϳ1.72 eV, in agreement with forward IV measurements. 14 As opposed to the 4H-SiC polytype, results from the 6H-SiC polytype showed two high-energy thresholds, which could not be explained by the calculated 6H-SiC band structure. Figure 2 shows the BEES spectrum of Pt/6H-SiC and its first and second derivatives.…”

Interface metallization and electrical characterization of Ta–Pt multilayers on n-type SiC

“…Noble metal platinum is one of the most commonly used metals for both ohmic and Schottky contacts on SiC [8][9][10][11][12]. Solid-state reactions of Pt thin films with single-crystalline SiC have been studied for b-SiC [8,9] as well as for a-SiC [10,11].…”

“…Solid-state reactions of Pt thin films with single-crystalline SiC have been studied for b-SiC [8,9] as well as for a-SiC [10,11]. A reaction between the Pt and the SiC substrate is observed at temperatures of 600 8C and above [11], bringing a two-phase reaction zone comprising Pt-silicide and amorphous C [8,9]. Consequently, the carbon accumulation both at the interface and in the metal layer left behind during the silicidation process will certainly affect the electrical performance of the metallization.…”