Schottky barrier height and electron affinity of titanium on AIN

Contributors:   B.L. Ward, J.D. Hartman, E.H. Hurt, K.M. Tracy, R.F. Davis, and Robert J. Nemanich

ABSTRACT

Approximately 100 or 1000 Å of AlN was deposited on the (0001)Si-face of on-axis n-type 6H-SiC. The surfaces were examined by ultraviolet photoemission spectroscopy (UPS) utilizing the He I α (21.2 eV) and the He II α (40.8 eV) excitation. Experimental difficulties are discussed. Titanium was deposited on the clean surface of in situ grown AlN. The titanium-AlN interface was also characterized with UPS. Two approaches are presented to identify the valence band maximum (VBM) and the electron affinity χ of the clean surface of AlN was found to be either 0 to 1 eV depending upon the position of the valence band edge. The same assumptions were applied to the analysis of the Ti/AlN interface and, for the case of χ=0 eV, the position of the valence band maximum is 3.4 eV below the position of the Fermi level. For the case of χ=1 eV, the position of the valence band maximum is 4.4 eV below the position of the Fermi level. Therefore, the p-type Schottky barrier height of titanium on AlN is measured to be 3.4±0.2 or 4.4±0.2 eV for χ=0 eV and χ=1 eV, respectively. Independent of the selection of the valence band maximum, the observed Schottky barrier differed from that predicted by the Schottky-Mott model by 1.5±0.2 eV.

Publisher: Journal of Vacuum Science and Technology B: Microelectronics and nanometer Structures,   Volume: 18,   2082-2087 ||  Published: 2000-01 ||   Read more...