| 摘要 |
Hillock formation as a result of heating uncapped polycrystalline silicon layers can be avoided by first implanting the uncapped poly layers with silicon, oxygen, or nitrogen prior to heating. Equivalent mono-atomic oxygen or nitrogen doses in the range of about 1015 to about 5x1016 ions/cm2 at energies in the range 10-50 keV are useful with good results being obtained with equivalent oxygen doses of 2x1015 ions/cm2 at 30 keV. When polysilicon layers with this oxygen implant are heated to about 1150 degrees C., a temperature which would ordinarily produce pronounced hillock formation in un-capped, un-treated poly layers, it is found that hillock formation is suppressed. The implanted oxygen concentrations are far below what is required to produce a separate oxide layer or phase. Some effect on poly layer sheet resistance is observed for implanted oxygen but the implanted layers have sheet resistances within a factor of two of those without the oxygen implants. |
