Dopant activation anneal to achieve less dopant diffusion (better USJ profile) and higher activation percentage
AssigneeApplied Materials, Inc.
InventorZhi Xu
Life of this patent
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Abstract
A method and apparatus for forming a semiconductor device. A semiconductor substrate is implanted with dopants. The substrate is subjected to a cleaning process employing electrically neutral nitrogen and fluorine radicals to produce an oxygen-free surface having dangling bonds. Before any further exposure to oxidizing gases, the substrate is annealed by thermal treatment to activate and distribute the dopants. A gate oxide layer is formed over the annealed surface. The apparatus performs all such treatments without breaking vacuum.
Claims13
A method of processing a doped semiconductor substrate, comprising:
- disposing the doped semiconductor substrate in a processing chamber;
- providing a cleaning gas comprising a mixture of ammonia, nitrogen trifluoride, and a carrier gas to the processing chamber;
- converting a portion of the cleaning gas to neutral radicals by applying RF power;
- forming a sublimation layer on the doped semiconductor substrate by exposing the substrate to the cleaning gas while cooling the substrate;
- forming an oxygen-free surface on the doped semiconductor substrate by heating the sublimation layer;
- and
- activating the dopants in the doped semiconductor substrate by an annealing process, wherein a partial pressure of oxidizing gases is maintained below about 1 mTorr during the aforementioned disposing, providing, converting, forming, forming, and activating.
A process for forming a device on a substrate, comprising:
- implanting dopants into a surface of the substrate;
- terminating the implanted surface with dangling bonds by exposing the substrate to a reducing gas at a temperature less than about 100° C.;
- activating the dopants by heating the implanted surface of the substrate;
- and
- forming an oxide layer over the implanted surface.
A method of forming a device on a substrate, comprising:
- implanting dopants into a surface of the substrate;
- disposing the substrate in a processing chamber configured to produce a charge-free reducing gas comprising neutral radicals;
- applying RF energy at a remote location to form neutral radicals comprising nitrogen and fluorine;
- flowing the neutral radicals into the processing chamber and exposing the doped surface of the substrate to the neutral radicals;
- reacting the neutral radicals with the substrate surface at a temperature less than about 100° C. to form a thin film;
- removing the thin film by heating a fixture of the processing chamber, positioning the fixture near the substrate surface, and heating the substrate surface;
- generating dangling bonds on the substrate surface;
- activating the dopants using a furnace annealing process;
- and
- forming an oxide layer over the implanted surface.
Dependencies are inferred from the claim text.