Removal of the process-induced fluorine associated to chemical vapor deposition of tungsten onto a polycrystalline silicon gate structure by heat treatment in a hydrogen-containing atmosphere
- 1 September 1990
- journal article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 68 (5) , 2112-2120
- https://doi.org/10.1063/1.346566
Abstract
Tungsten was deposited from a gas mixture of hydrogen and tungsten hexafluoride onto a polycrystalline silicon gate structure in a chemical vapor deposition system. During the deposition process fluorine was also deposited as an undesired impurity. In order to remove the fluorine, heat treatments in the temperature range 550–1050 °C were performed in a hydrogen atmosphere. By this treatment it is possible to form volatile hydrofluoric acid and hence remove fluorine from the structure. Nuclear-resonance-broadening technique and secondary ion mass spectrometry were used for the analysis of fluorine. Fluorine was detected in all the samples except for the sample heat treated at 1050 °C. Moreover, etching of the polycrystalline silicon was observed. The gettering of fluorine, the etching of silicon and the observed formation of tungsten disilicide at 650 °C are discussed with respect to conceivable mechanisms. A thermodynamic study supporting the interpretations is also included.This publication has 20 references indexed in Scilit:
- Ion-implantation-induced fluorine agglomeration in tungsten disilicide prepared by low-pressure chemical vapour depositionNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1989
- Dielectric characteristics of fluorinated ultradry SiO2Applied Physics Letters, 1989
- Fluorine redistribution in a chemical vapor deposited tungsten/polycrystalline silicon gate structure during heat treatmentJournal of Applied Physics, 1988
- Dramatic improvement of hot-electron-induced interface degradation in MOS structures containing F or Cl in SiO/sub 2/IEEE Electron Device Letters, 1988
- Effect of fluorine in chemical-vapor-deposited tungsten silicide film on electrical breakdown of SiO2 filmJournal of Applied Physics, 1987
- Fluorine distributions in a chemical vapor deposited tungsten silicide/polycrystalline silicon composite gate structureApplied Physics Letters, 1987
- Processes in interfacial zones during chemical vapour deposition: Aspects of kinetics, mechanisms, adhesion and substrate atom transportThin Solid Films, 1985
- Selective Low Pressure Chemical Vapor Deposition of TungstenJournal of the Electrochemical Society, 1984
- Effect of scaling of interconnections on the time delay of VLSI circuitsIEEE Transactions on Electron Devices, 1982
- Investigation of parameter sensitivity of short channel mosfetsSolid-State Electronics, 1982