CONTROL OF INTERNAL-STRESS AND YOUNG MODULUS OF SI3N4 AND POLYCRYSTALLINE SILICON THIN-FILMS USING THE ION-IMPLANTATION TECHNIQUE

Boron and phosphorus ions are implanted in order to control the internal stress and Young's modulus of 200-nm-thick silicon nitride and polycrystalline silicon films prepared by low-pressure chemical vapor deposition. These ions are implanted into the middle layer of the films at doses of 1×10 14 and 1×1015/cm2, then the films are annealed at 900°C. The internal stress and Young's modulus of these films are measured by a rectangular membrane load deflection technique [Tech. Digest, IEEE Micro Electromechanical Systems Workshop, IEEE, Salt Lake City, UT, 1989, p. 152]. Both internal stress and Young's modulus of the silicon nitride film decrease with dose, while those of the polycrystalline silicon film do not necessarily decrease.