STRUCTURAL AND ELECTRICAL CHANGES IN POLYCRYSTALLINE SILICON THIN-FILMS THAT ARE HEAVILY IN-SITU BORON-DOPED AND THERMALLY OXIDIZED WITH DRY OXYGEN

In this paper, we investigate some particular aspects of changes in th e thermal behavior polycrystalline silicon films deposited by low pres sure chemical vapor deposition (LPCVD). The results will concern chang es in both the structural and electrical properties of heavily (2 x 10 (20) cm(-3)) in situ boron-doped thin films before and after thermal-o xidation treatments. Secondary ion mass spectrometry (SIMS), transmiss ion electron microscopy (TEM), and four-point-probe resistivity (FPPR) measurements were carried out on submicrometer layers (approximate to 300 nm) deposited at two interesting temperatures T-d = 520 degrees C and T-d = 605 degrees C. The thermal-oxidation experiments are perfor med under dry O-2 at three oxidation temperatures T-ox = 840, 945, and 1050 degrees C for several durations. Remarkable changes in the behav ior of doping profile, grain growth, and electrical conductivity were observed. While the kinetic-oxidation analyses reveal the presence of a ''differential oxidation rate (DOR)'' between the two layers, recrys tallization effects show a similar behavior, called ''differential gro wth mechanism (DGM)'', between the same layers. These observations see m to be characteristic of the in situ heavily boron-doped films, consi stent with results of a previous study.