Advanced technique to improve the bonding arrangement on silicon surfaces to promote uniform nitridation

摘要

The present invention teaches a method for fabricating an ultrathin uniform dielectric layer over a silicon or polysilicon semiconductor substrate. The method entails first providing a substrate having a conductive area into a chamber. Subsequently, the first conductive material is destabilized by introducing it to reactive gas and radiant energy in situ. The reactive gas can be Ar-H.sub.2, H.sub.2, GeH. sub.4 or NF.sub.3 gas. The radiant energy source can be ultraviolet ("UV") or Tungsten Halogen lamps preferably having an approximate range of 0.2 to 1. 6 &mgr;m to provide heat of approximately 850° to 1150° C. for approximately 10 to 60 seconds at a vacuum pressure range of 10.sup.- 10 Torr to atmospheric pressure. This process removes the native oxide and breaks the molecular clusters present on the silicon or polysilicon surface. Thereafter, a first dielectric layer having a substantially uniform thickness forms directly above the substrate by the in situ introduction of NH.sub.3 with the radiant energy generating heat of approximately 850° to 1150° C. for approximately 10 to 60 seconds at a vacuum pressure range of 10.sup.-10 Torr to atmospheric pressure. Finally, a second silicon nitride layer is deposited by low pressure chemical vapor deposition or plasma nitridation to create a combined thickness of both dielectric layers of 40 to 100 Å.