Method and structure for inhibiting dopant out-diffusion
AssigneeFairchild Camera and Instrument Corporation
InventorsMichael E. Thomas, Madhukar B. Vora, Ashok K. Kapoor
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Abstract
A method for inhibiting out-diffusion of dopants from polycrystalline or single crystal silicon substrates of high speed semiconductor devices into metal silicide conductive layers disposed on the substrate comprises interposing a refractory metal nitride layer between the doped silicon substrate and the refractory metal silicide conductive layer. Dopant out-diffusion is further retarded, and contact resistance lowered, by adding a thin layer of refractory metal between the refractory metal nitride layer and the silicon substrate.
Claims29
A method of inhibiting dopant out-diffusion in a semiconductor device including a silicon substrate containing a dopant and having a refractory metal silicide layer disposed on at least a portion of one surface thereof, said method comprising the step of disposing a refractory metal nitride barrier layer between said doped silicon substrate and said refractory metal silicide layer.
A method of inhibiting dopant diffusion in a high speed semiconductor device, said method comprising the steps of:
- (a) providing a silicon substrate containing a dopant and having a first surface;
- (b) disposing a first layer of a first refractory metal over the first surface of said substrate, said first layer having a predetermined thickness;
- (c) depositing a second refractory metal on said first layer in an ambient environment having a predetermined concentration of nitrogen in order to form a blanket layer of a refractory metallic nitride having a predetermined thickness;
- (d) placing an amorphous, co-deposited third refractory metal:
- silicon layer, having a predetermined thickness and a predetermined atomic ratio of silicon to refractory metal, on said blanket layer;
- and
- (e) transforming said co-deposited layer to a refractory metallic dicilicide layer by heating at a predetermined temperature for a predetermined amount of time in a second predetermined ambient environment.
In a semiconductor device including a silicon substrate containing a dopant and having a first refractory metal layer disposed on at least one portion of one surface thereof, a method of blocking silicon transport from said substrate to said first refractory metal layer comprising the step of disposing a refractory metal nitride barrier layer between said substrate and said first refractory metal layer.
Dependencies are inferred from the claim text.