Laser annealed double conductor structure
AssigneeHughes Aircraft Company
InventorsGiora Yaron, LaVerne D. Hess
Life of this patent
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Abstract
In double conductor micro-electronic structures, prior to the low temperature deposition or growth of an insulating layer over a polycrystalline or amorphous surface, the surface is annealed using a beam of radiant energy, which causes it to become very smooth, thereby removing any surface spikes. The insulating layer placed thereover has remarkably improved insulation qualities heretofore unattainable at low temperatures. The beam of radiant energy is preferably applied in bursts of energy lasting for a sufficiently short duration so that implanted impurities in the silicon substrate do not redistribute.
Claims27
A method for growing improved oxide over a polycrystalline silicon layer overlying a silicon substrate, said substrate having dopant impurities, comprising:
- depositing a polycrystalline silicon layer over said substrate;
- exposing said polycrystalline silicon layer to a beam of energy of sufficient magnitude to cause removal of surface defects in said polycrystalline silicon layer, said energy beam being of sufficiently short duration to prevent substantial redistribution of said impurities;
- and,
- growing silicon dioxide over said polycrystalline silicon layer at a sufficiently low temperature to prevent substantial redistribution of said impurities, said silicon dioxide having a susceptibility to leakage current therethrough which is reduced in proportion to the previous removal of said surface defects by said exposing step.
A method for fabricating a metal oxide semiconductor device having a polycrystalline silicon layer and a conductor overlying said layer, said device having improved insulation between said polycrystalline silicon layer and said overlying conductor, comprising:
- forming a layer of polycrystalline silicon;
- exposing said polycrystalline silicon layer to a beam of energy of sufficient magnitude to smooth surface defects in said polycrystalline silicon layer;
- growing a film of silicon dioxide over said polycrystalline silicon layer at a sufficiently low temperature to prevent substantial thermal changes in said metal oxide semiconductor device, said silicon dioxide film having a susceptibility to leakage currents therethrough which is reduced in proportion to the previous smoothing of said surface defects by said exposing step;
- and
- depositing a conductor on said silicon dioxide layer, said conductor overlying said polycrystalline silicon layer.
A method for placing improved insulation over a material layer overlying a substrate wherein said material layer comprises one of an amorphous material and a polycrystalline material, said method comprising:
- first placing said material layer over said substrate;
- exposing said material layer to a beam of energy of sufficient magnitude to smooth surface defects in said material layer;
- second placing an insulating film over said material layer at a sufficiently low temperature to prevent substantial thermal changes in said substrate, said insulating film having a susceptibility to leakage currents therethrough which is reduced in proportion to the previous smoothing of said surface defects by said exposing step;
- and
- third placing a conductor layer over said insulating film.
A method for placing improved insulation over an amorphous material overlying a substrate, comprising:
- first placing an amorphous material layer over said substrate;
- exposing said amorphous material layer to a beam of energy of sufficient magnitude to cause removal of surface defects in said amorphous layer;
- and
- second placing an insulating film over said amorphous material layer at a sufficiently low temperature so as to prevent thermal changes from occuring in said substrate during said second placing step, said insulating film having a susceptibility to leakage currents which is reduced in proportion to said removal of said surface defects by said exposing step.
A method for placing improved insulation over a polycrystalline material overlying a substrate, comprising:
- first placing a polycrystalline material layer over said substrate;
- exposing said polycrystalline material layer to a beam of energy of sufficient magnitude to cause removal of surface defects in said polycrystalline material layer;
- and
- second placing an insulating film over said polycrystalline material layer at a temperature sufficiently low so as to substantially prevent thermal changes in said substrate during said second placing step, said insulating film having a susceptibility to leakage currents which is reduced in proportion to said removal of said surface defects by said exposing step.
Dependencies are inferred from the claim text.