Gas control technique for limiting surging of gas into a CVD chamber

Abstract

In one embodiment, a method of forming a barrier layer for contacting a metal interconnect layer to one or more exposed N and P type silicon regions on a wafer. The wafer is heated with a direct radiation source, such as a lamp. To equalize the differing emissivities of the N type and P type silicon regions, an opaque layer of refractory metal is first formed on the regions at a temperature below approximately 100.degree. C. A refractory metal deposition process is then conducted at temperatures between 230.degree.-425.degree. C. During this higher temperature deposition process, the reducing gas is ramped up with time to increase the deposition rate of the refractory metal as the exothermic reducing reactions increasingly heat the contact areas. Other process and apparatus features enable higher bonding strength between the silicon surface and the formed barrier layer contacting the silicon surface and enable a higher purity content of the processing gases as well as improved diffusion of processing gases when injected into the processing chamber.

Dependencies are inferred from the claim text.