NONUNIFORM OXIDE CHARGE AND PARAMAGNETIC INTERFACE TRAPS IN HIGH-TEMPERATURE ANNEALED SI SIO2/SI STRUCTURES/

Trivalent silicon P-b0 and P-b1 defects were identified at both the to p Si(100)/buried-SiO2 and buried-SiO2/bottom-Si(100) interfaces in hig h-temperature (1320 degrees C) annealed Si/SiO2/Si structures. The par amagnetic defects are generated by annealing in a flow of pure nitroge n (N-2) or forming gas [N2H2; 95:5 (by volume)] at 550 degrees C. In a ddition, the forming-gas anneal also generated positive charge in the buried oxides; significant lateral nonuniformities in the buried oxide charge density were observed following this anneal. These macroscopic inhomogeneities may be linked to previous reports of homogeneity rela ted problems involving the SIMOX buried oxide, such as early breakdown and etch pits, suggesting that these types of measurements may be use ful as nondestructive screens of SIMOX wafer quality. (C) 1996 America n Institute of Physics.