Sequential chemical vapor deposition

Abstract

The present invention provides for sequential chemical vapor deposition by employing a reactor operated at low pressure, a pump to remove excess reactants, and a line to introduce gas into the reactor through a valve. A first reactant forms a monolayer on the part to be coated, while the second reactant passes through a radical generator which partially decomposes or activates the second reactant into a gaseous radical before it impinges on the monolayer. This second reactant does not necessarily form a monolayer but is available to react with the monolayer. A pump removes the excess second reactant and reaction products completing the process cycle. The process cycle can be repeated to grow the desired thickness of film.

1 . An apparatus for growing a thin film comprising: 
 a reaction chamber configured to contain at least one substrate;    a first reactant vapor source in selective communication with the reaction chamber;    a second reactant vapor source in selective communication with the reaction chamber;    an excess vapor removal system in communication with the reaction chamber;    a device configured to cause at least a portion of the reactant vapors within the reaction chamber to form vapor fragments selectively in time; and    a controller configured to introduce vapor reactants from the first reactant vapor source and second reactant vapor source to the reaction chamber in alternate and sequential pulses to deposit a desired film by atomic layer deposition on a substrate when the substrate is present in the reaction chamber.    
   
   
       2 . The apparatus of  claim 1 , wherein the reaction chamber is configure to support a single semiconductor wafer.  
   
   
       3 . The apparatus of  claim 1 , wherein the first reactant vapor source, the second reactant vapor source, and the excess vapor removal system each further comprise a valve, wherein the controller is configured to control said valves.  
   
   
       4 . The apparatus of  claim 1 , wherein the controller is further configured to cause the device to form vapor fragments from the second reactant vapor when pulsed within the reaction chamber.  
   
   
       5 . The apparatus of  claim 4 , wherein the second reactant vapor source comprises diatomic oxygen.  
   
   
       6 . The apparatus of  claim 4 , wherein the second reactant vapor source comprises diatomic hydrogen.  
   
   
       7 . The apparatus of  claim 1 , further comprising a carrier gas source in communication with the reaction chamber, wherein the controller is further configured to introduce the alternate and sequential pulses with carrier gas from the carrier gas source.  
   
   
       8 . The apparatus of  claim 1 , wherein the first reactant vapor source comprises a metal source compound.  
   
   
       9 . The apparatus of  claim 1 , wherein the first reactant vapor source comprises a non-semiconductor precursor.  
   
   
       10 . The apparatus of  claim 1 , wherein the controller is configured to deposit a non-semiconductor film.  
   
   
       11 . The apparatus of  claim 1 , further comprising at least one additional reactant vapor source in selective communication with the reaction chamber, wherein the controller is configured to introduce to the reaction chamber pulses from the additional reactant vapor source alternately and sequentially with pulses of vapor from the first and second reactant vapor sources.  
   
   
       12 . The apparatus of  claim 11 , wherein the controller is configured such that a ratio of pulses from the reactant vapor sources is not one-to-one to correspond with a desired stoichiometry of the desired film.  
   
   
       13 . The apparatus of  claim 1 , wherein the vapor exhaust system is further configured to remove from the reaction chamber substantially all excess species of vapor from one of the alternate and sequential pulses before introduction of vapor from a subsequent pulse.  
   
   
       14 . The apparatus of  claim 1 , further comprising a purge gas source in selective communication with the reaction chamber, wherein the controller is further configured to introduce a quantity of purge gas from the purge gas source to the reaction chamber between the alternate and sequential pulses.  
   
   
       15 . The apparatus of  claim 14 , wherein the quantity of purge gas replaces substantially all reactant vapor from the first and second reactant vapor sources from the reaction chamber between the alternate and sequential pulses.  
   
   
       16 . The apparatus of  claim 14 , wherein the purge gas source comprises a same gas as contained in the second reactant vapor source, wherein the controller is configured to continuously supply the purge gas and periodically employ the device to cause the purge gas to form vapor fragments, wherein the vapor fragments comprise one of the pulses of the reactant vapors.  
   
   
       17 . The apparatus of  claim 1 , wherein the controller is further configured to maintain a temperature of the substrate during deposition above the condensation limit of the first reactant vapor.  
   
   
       18 . The apparatus of  claim 17 , wherein the controller is further configured to maintain a temperature of the substrate during deposition below 300 degrees Celsius.  
   
   
       19 . The apparatus of  claim 17 , wherein the controller is further configured to maintain a temperature of the substrate during deposition of about room temperature.  
   
   
       20 . The apparatus of  claim 1 , wherein the device comprises a solenoidal coil surrounding the reaction chamber.  
   
   
       21 . The apparatus of  claim 1 , wherein the device is configured to generate vapor fragments within the reaction chamber in pulses from the second reactant vapor source for reaction with a monolayer formed by a prior pulse from the first reactant vapor source on the substrate.  
   
   
       22 . The apparatus of  claim 1 , wherein the device comprises at least two electrodes configured to generate an electric field.  
   
   
       23 . The apparatus of  claim 1 , wherein the device comprises an RF power source.  
   
   
       24 . The apparatus of  claim 1 , wherein the first reactant vapor source communicates with the reaction chamber at an inlet at a first end of the reaction chamber, the excess vapor removal system communicates with the reaction chamber at an outlet at a second end of the reaction chamber, wherein the inlet and outlet define a substantially lateral flow path across the substrate when supported in the reaction chamber.  
   
   
       25 . The apparatus of  claim 1 , further comprising a non-electrically conducting substrate holder within the reaction chamber.  
   
   
       26 . The apparatus of  claim 1 , wherein the reaction chamber is formed by a dielectric ceramic material.  
   
   
       27 . The apparatus of  claim 1 , wherein the first reactant vapor source comprises a vaporizer for a solid or liquid reactant.  
   
   
       28 . An apparatus for growing a thin film comprising: 
 a reaction chamber configured to contain at least one target substrate;    a first reactant vapor source connected to the reaction chamber;    a second reactant vapor source connected to the reaction chamber;    an excess vapor removal system connected to the reaction chamber;    a device configured to cause at least a portion of the reactant vapors outside the reaction chamber to form vapor fragments selectively in time; and    a controller configured to alternately and sequentially introduce pulses of reactant vapor from the first reactant vapor source and second reactant vapor source to the reaction chamber, such that a desired film is deposited by atomic layer deposition on the target substrate when the target substrate is present in the reaction chamber;    wherein the first reactant vapor source is a metal precursor.    
   
   
       29 . The apparatus of  claim 28 , wherein the sources and controller are configured to deposit a non-semiconductor film.  
   
   
       30 . The apparatus of  claim 28 , wherein the excess vapor removal system is further configured to remove from the vicinity of the target substrate substantially all excess species of vapor from one of the pulses before introduction of vapor from a subsequent pulse.  
   
   
       31 . The apparatus of  claim 28 , further comprising a purge gas source in selective communication with the reaction chamber, wherein the controller is further configured to introduce a quantity of purge gas from the purge gas source to the reaction chamber between the pulses.  
   
   
       32 . The apparatus of  claim 31 , wherein the quantity of purge gas replaces substantially all vapor from the first and second reactant sources from the vicinity of the target substrate.  
   
   
       33 . The apparatus of  claim 31 , wherein the purge gas source is the second reactant vapor source, wherein the controller is configured to continuously supply the purge gas from the second reactant vapor source and periodically cause the remote vapor fragment generator to form vapor fragments from the purge gas, wherein the vapor fragments form one of the reactant pulses.  
   
   
       34 . The apparatus of  claim 28 , wherein the controller is further configured to maintain a temperature of the target substrate during deposition below  300  degrees Celsius.  
   
   
       35 . The apparatus of  claim 28 , wherein the controller is further configured to maintain a temperature of the target substrate during deposition of about room temperature.  
   
   
       36 . The apparatus of  claim 28 , wherein the device and the first reactant vapor source have separate inlets to the reaction chamber.  
   
   
       37 . The apparatus of  claim 28 , wherein the device comprises at least two electrodes configured to generate an electric field outside of the reaction chamber.  
   
   
       38 . The apparatus of  claim 28 , wherein said device comprises an RF power source.  
   
   
       39 . An apparatus for growing a thin film comprising: 
 a reaction chamber comprising a wafer holder;    a first reactant vapor source connected to the reaction chamber;    a remote vapor fragment generator connected to the reaction chamber;    a second reactant vapor source connected to the reaction chamber through the remote vapor fragment generator;    an excess vapor removal system connected to the reaction chamber; and    a controller configured to cause pulses of reactant vapor from the first reactant vapor source and second reactant vapor source to be introduced alternately and sequentially to the reaction chamber to deposit a desired film by atomic layer deposition on a wafer supported by the wafer holder;    wherein the first reactant vapor source and the excess vapor removal system define a vapor flow path through the reaction chamber substantially parallel to a major surface of the wafer holder.    
   
   
       40 . The apparatus of  claim 39 , wherein the first reactant vapor source and the excess vapor removal system define a substantially horizontal vapor flow path.  
   
   
       41 . The apparatus of  claim 39 , wherein the sources and controller are configured to deposit a non-semiconductor film.  
   
   
       42 . The apparatus of  claim 39 , wherein the excess vapor removal system is further configured to remove from the vicinity of the target substrate substantially all excess species of vapor from one of the pulses before introduction of vapor from a subsequent pulse.  
   
   
       43 . The apparatus of  claim 39 , further comprising a purge gas source in selective communication with the reaction chamber, wherein the controller is further configured to introduce a quantity of purge gas from the purge gas source to the reactor chamber between said pulses.  
   
   
       44 . The apparatus of  claim 43 , wherein the quantity of purge gas replaces substantially all vapor from the first and second reactant sources from the vicinity of the target substrate.  
   
   
       45 . The apparatus of  claim 43 , wherein the purge gas source comprises the second reactant vapor source, wherein the controller is configured to continuously supply the purge gas to the reaction chamber through the remote vapor fragment generator and to periodically cause the remote vapor fragment generator to form vapor fragments from the reactant vapors, wherein the vapor fragments form one of the reactant pulses.  
   
   
       46 . The apparatus of  claim 39 , wherein the controller is further configured to maintain a temperature of the target substrate during deposition below  300  degrees Celsius.  
   
   
       47 . The apparatus of  claim 39 , wherein the controller is further configured to maintain a temperature of the target substrate during deposition of about room temperature.  
   
   
       48 . The apparatus of  claim 39 , wherein the remote vapor fragment generator and the first reactant vapor source have separate inlets to the reaction chamber.  
   
   
       49 . The apparatus of  claim 39 , wherein the remote vapor fragment generator comprises at least two electrodes configured to generate an electric field for exciting reactant source vapor from the second reactant vapor source.  
   
   
       50 . The apparatus of  claim 39 , wherein the remote vapor fragment generator comprises a RF power source.