HIGH-TEMPERATURE LOCAL OXIDATION OF SILICON FIELD ISOLATION MORPHOLOGICAL CHARACTERIZATION

The morphological characterization of local oxidation of silicon (LOCO S) isolation has been carried out by using steam oxidation in the temp erature range 1050 to 1180 degrees C and as-grown field oxide thicknes s between 150 and 600 nm. A bird's beak minimum is observed between 11 00 and 1140 degrees C, corresponding to a change in the bird's beak gr owth mechanism from a diffusion type to a regime dependent on silicon surface oxidation and nitride oxidation rates. For the first time on L OCOS isolation, the improvement of field oxide thinning by reducing fi eld oxide thickness is reported: that enables a possible scaling for s ubquarter micrometer design rules.