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Higher Resistivity Trench Fills

IP.com Disclosure Number: IPCOM000044018D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Silvestri, VJ: AUTHOR

Abstract

Existing CVD (chemically vapor deposited) depositions using homogeneous gas phase reactions are employed for trench fills in semiconductor processing. The results are sometimes unsatisfactory when filling trenches with SiO2 or Si3N4, particularly when high trench densities are called for or poorly shaped trenches are involved. A heterogeneous reaction (solid-gas) along with the use of nucleating polysilicon film has been found, on the other hand, to produce better polysilicon refills in such trench structures. No comparable use of a heterogeneous reaction has been noted in existence for the deposition of SiO2 in a similar manner. This article describes the use of a heterogeneous reaction, based on the use of SiCl4 chemistry, for the deposition of semi-insulating and insulating films of SixOy or SixNy .

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Higher Resistivity Trench Fills

Existing CVD (chemically vapor deposited) depositions using homogeneous gas phase reactions are employed for trench fills in semiconductor processing. The results are sometimes unsatisfactory when filling trenches with SiO2 or Si3N4, particularly when high trench densities are called for or poorly shaped trenches are involved. A heterogeneous reaction (solid-gas) along with the use of nucleating polysilicon film has been found, on the other hand, to produce better polysilicon refills in such trench structures. No comparable use of a heterogeneous reaction has been noted in existence for the deposition of SiO2 in a similar manner. This article describes the use of a heterogeneous reaction, based on the use of SiCl4 chemistry, for the deposition of semi-insulating and insulating films of SixOy or SixNy . Silicon-rich oxides and nitrides have been achieved using SiH4 with N2O and NH3 at 700OEC. Reactions of a heterogeneous type, which could be used to obtain higher resistivity trench fills while simultaneously providing for a good fill, are the following: 1. 3SiCl4 + 4NH3 Si3N4 + 12HCl (900-1000 C);OEand 2. SiCl4 + 2CO2 + H2 SiO2 + 4HCl (950- 1000 C) The use of these reactions with a thin nucleating layer similar to that employed with the heterogeneous reaction with polysilicon refills, along with variation of partial pressures of reactants in equations (1) and (2) above, would provide for variations of silicon content in SixNy and Si...