Formation method of semiconductor device with oxide semiconductor channel

Abstract

A method for forming a semiconductor device structure is provided. The method includes forming a stack over a substrate. The stack has multiple sacrificial layers and multiple oxide semiconductor layers laid out alternately. The method also includes partially removing the sacrificial layers to expose inner portions of the oxide semiconductor layers. The inner portions of the oxide semiconductor layers form multiple oxide semiconductor nanostructures. The method further includes changing an atomic concentration of oxygen of the oxide semiconductor nanostructures. In addition, the method includes forming a gate stack wrapped around one or more of the oxide semiconductor nanostructures after the changing of the atomic concentration of oxygen of the oxide semiconductor nanostructures.

What is claimed is: 
     
         1 . A method for forming a semiconductor device structure, comprising:
 forming a stack over a substrate, wherein the stack has a plurality of sacrificial layers and a plurality of oxide semiconductor layers laid out alternately;   partially removing the sacrificial layers to form a recess exposing portions of the oxide semiconductor layers, wherein inner portions of the oxide semiconductor layers exposed by the recess form a plurality of oxide semiconductor nanostructures;   introducing oxygen into the oxide semiconductor nanostructures; and   forming a gate stack wrapped around at least one of the oxide semiconductor nanostructures.   
     
     
         2 . The method for forming a semiconductor device structure as claimed in  claim 1 , wherein the introducing of oxygen into the oxide semiconductor nanostructures is performed by annealing the oxide semiconductor nanostructures under an oxygen-containing atmosphere. 
     
     
         3 . The method for forming a semiconductor device structure as claimed in  claim 1 , further comprising reducing an atomic concentration of oxygen of outer portions of the oxide semiconductor layers, wherein the outer portions of the oxide semiconductor layers sandwich the oxide semiconductor nanostructures. 
     
     
         4 . The method for forming a semiconductor device structure as claimed in  claim 3 , wherein the reducing of the atomic concentration of oxygen of the outer portions of the oxide semiconductor layers is performed by annealing the outer portions of the oxide semiconductor layers under an atmosphere containing substantially no oxygen. 
     
     
         5 . The method for forming a semiconductor device structure as claimed in  claim 3 , wherein the reducing of the atomic concentration of oxygen of the outer portions of the oxide semiconductor layers is performed before the introducing of oxygen into the oxide semiconductor nanostructures. 
     
     
         6 . The method for forming a semiconductor device structure as claimed in  claim 1 , further comprising forming a plurality of oxygen-scavenging layers, wherein each of the oxygen-scavenging layers is formed on a respective oxide semiconductor layer of the oxide semiconductor layers, and the atomic concentration of oxygen of the outer portions of the oxide semiconductor layers are reduced by annealing the oxide semiconductor layers and the oxygen-scavenging layers under an atmosphere containing substantially no oxygen. 
     
     
         7 . The method for forming a semiconductor device structure as claimed in  claim 6 , wherein the oxygen-scavenging layers comprises titanium, titanium nitride, tungsten, or a combination thereof. 
     
     
         8 . The method for forming a semiconductor device structure as claimed in  claim 1 , further comprising:
 trimming the oxide semiconductor nanostructures before the gate stack is formed.   
     
     
         9 . The method for forming a semiconductor device structure as claimed in  claim 8 , wherein the introducing of oxygen into the oxide semiconductor nanostructures is performed after the trimming of the oxide semiconductor nanostructures. 
     
     
         10 . The method for forming a semiconductor device structure as claimed in  claim 1 , wherein a lower portion of the gate stack is formed under the oxide semiconductor nanostructures and an upper portion of the gate stack is formed above the oxide semiconductor nanostructures. 
     
     
         11 . The method for forming a semiconductor device structure as claimed in  claim 1 , further comprising:
 forming a dielectric filling wrapped around the oxide semiconductor nanostructures and portions of the gate stack.   
     
     
         12 . A method for forming a semiconductor device structure, comprising:
 forming a stack over a substrate, wherein the stack has a plurality of sacrificial layers and a plurality of oxide semiconductor layers laid out alternately;   partially removing the sacrificial layers to expose inner portions of the oxide semiconductor layers, wherein the inner portions of the oxide semiconductor layers form a plurality of oxide semiconductor nano structures;   changing a first atomic concentration of oxygen of the oxide semiconductor nanostructures; and   forming a gate stack wrapped around at least one of the oxide semiconductor nanostructures after the changing of the atomic concentration of oxygen of the oxide semiconductor nanostructures.   
     
     
         13 . The method for forming a semiconductor device structure as claimed in  claim 12 , further comprising:
 changing a second atomic concentration of oxygen of outer portions of the oxide semiconductor layers.   
     
     
         14 . The method for forming a semiconductor device structure as claimed in  claim 13 , wherein the changing of the second atomic concentration of oxygen is performed after the changing of the first atomic concentration of oxygen. 
     
     
         15 . The method for forming a semiconductor device structure as claimed in  claim 14 , wherein the changing of the first atomic concentration of oxygen is performed under an oxygen-containing atmosphere, and the changing of the second atomic concentration of oxygen is performed under an atmosphere containing substantially no oxygen. 
     
     
         16 . The method for forming a semiconductor device structure as claimed in  claim 12 , further comprising:
 trimming the oxide semiconductor nanostructures before the changing of the first atomic concentration of oxygen.   
     
     
         17 . A method for forming a semiconductor device structure, comprising:
 forming a semiconductor nanostructure over a substrate;   trimming an inner portion of the semiconductor nanostructure;   introducing oxygen into the inner portion of the semiconductor nanostructure; and   forming a gate stack over the inner portion of the semiconductor nanostructure, wherein a portion of the gate stack is between the semiconductor nanostructure and the substrate.   
     
     
         18 . The method for forming a semiconductor device structure as claimed in  claim 17 , further comprising:
 driving oxygen originally in outer portions of the semiconductor nanostructure to leave the outer portions of the semiconductor nanostructure.   
     
     
         19 . The method for forming a semiconductor device structure as claimed in  claim 18 , wherein the introducing of oxygen into the inner portion of the semiconductor nanostructure and the driving of oxygen originally in outer portions of the semiconductor nanostructure to leave the outer portions of the semiconductor nanostructure are performed separately. 
     
     
         20 . The method for forming a semiconductor device structure as claimed in  claim 18 , wherein the introducing of oxygen into the inner portion of the semiconductor nanostructure is performed before the driving of oxygen originally in outer portions of the semiconductor nanostructure to leave the outer portions of the semiconductor nanostructure.