ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A WSix≈2.6 film was deposited by low-pressure chemical vapor deposition at 350–420 °C onto a P-doped polycrystalline silicon/SiO2/Si substrate. This polycide structure (with or without a subsequent As+ source/drain implant) was heat treated in the following manner: (i) 1000 °C/N2 anneal for 20 min, (ii) oxidation both in dry oxygen and in steam ambients at 920–950 °C (50 min–8 h), and (iii) N2 anneal as well as dry oxidation at 920 °C/50 min. Cross-sectional transmission electron microscopy, Rutherford backscattering, secondary ion mass spectrometry, and sheet resistance measurements were used for characterization. The as-deposited film was mostly amorphous with a fine grain structure. The N2 anneal caused the formation of a polycrystalline WSix〉2 film containing tetragonal WSi2. Dry oxidation produced a void-containing SiO2 layer atop the silicide film. However, the SiO2 layer was impregnated with W particles when the silicide film was steam oxidized. The role of excess Si in refractory metal silicide films during annealing and oxidation is discussed. The effect of stress at the corners of a step in a patterned wafer during the oxidation of tungsten polycide is also demonstrated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.339414
