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 the thermal behavior polycrystalline silicon films deposited by low pressure chemical vapor deposition (LPCVD). The results will concern changes 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-oxidation treatments. Secondary ion mass spectrometry (SIMS), transmission 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 performed under dry O-2 at three oxidation temperatures T-ox = 840, 945, and 1050 degrees C for several durations. Remarkable changes in the behavior 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, recrystallization effects show a similar behavior, called ''differential growth mechanism (DGM)'', between the same layers. These observations seem to be characteristic of the in situ heavily boron-doped films, consistent with results of a previous study.