Abstract
We investigated the oxidation of crystallized tungsten suicide. We also researched the effects of preimplantation by P (or As) on the oxidation. Our results showed that the oxidation involved decomposition of the tungsten disilicide and consumption of the underlying polycrystalline silicon (polysilicon), consequently causing serious reliability problems. Cross-sectional transmission electron microscopy (XTEM) analysis showed that the oxide consisted of crystalline WO3 and amorphous SiO2, which was not removed completely using chemical solutions such as 100 : 1 HF and 7 : 1 buffered oxide etchant (BOE). However, P (or As) implantation prior to oxidation produced a SiO2 layer free of tungsten oxide. In particular, phosphorous implantation into silicide yielded a much thinner SiO2 layer on the silicide than As, which might be attributed to the presence of P2O5 in the oxide.
Original language | English |
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Pages (from-to) | 7140-7145 |
Number of pages | 6 |
Journal | Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers |
Volume | 36 |
Issue number | 12 A |
DOIs | |
State | Published - Dec 1997 |
Keywords
- Metal-free oxide
- Oxidation
- P (or As) implantation
- WSi