The Formation of Boron‐Doped Polycrystalline Si with Extremely Low Resistivities at Low Temperatures

Abstract

A process consisting of the deposition of amorphous silicon at low temperatures and subsequent annealing has been proposed for fabricating a boron-doped pelycrystalline silicon film with a low resistivity. This process realized large grain growth up to 3 to 5 ~m, leading to a low resistivity of 1.4 m~ • cm, which one-half to about one-third compared with that of direct deposited boron doped polysilicon. In addition to this, extremely low deposition temperature (~350°C) using a Si2HJB2H6 mixture attained uniform boron concentration across the wafers.

Investigation of In-situ Boron-Doped Si Selective Epitaxial Growth by Comparison with Arsenic Doping

“…The catalytic effects of B atoms were reported in the literature. 26,27) B atoms acted as a catalyst that enhances the decomposition of SiH 2 Cl 2 . The formation of an excited BH 5 SiH 3 complex enhances the deposition of Si atoms.…”

Theoretical Study of the Thermochemistry of Molecules in the Si−B−H−Cl System

“…For deposition of silicon from silane, the addition of a small amount of diborane (1.5 × 10 -3 of the silane concentration) is reported to double the deposition rate , although the effect decreases with increasing temperature. , For dichlorosilane, the addition of diborane (1 × 10 -3 of the dichlorosilane concentration) is reported to increase the deposition rate by 2 orders of magnitude . In contrast, for n-type dopants, the use of phosphine and arsine are reported to decrease deposition rates with silane, while increasing deposition rates with dichlorosilane …”

“…For deposition of silicon from silane, the addition of a small amount of diborane (1.5 × 10 -3 of the silane concentration) is reported to double the deposition rate. 4 For disilane, the addition of diborane (2 × 10 -4 of the disilane concentration) is reported to increase the deposition rate by more than a factor of 3 at lower temperatures, 5,6 although the effect decreases with increasing temperature. 5,7 For dichlorosilane, the addition of diborane (1 × 10 -3 of the dichlorosilane concentration) is reported to increase the deposition rate by 2 orders of magnitude.…”