Fabrication of localized soi on localized thick box using selective epitaxy on bulk semiconductor substrates for photonics device integration

Abstract

Photonic devices are created by laterally growing a semiconductor material (i.e., a localized semiconductor-on-insulator layer) over a localized buried oxide (BOX) created in a semiconductor by either a trench isolation process or thermal oxidation. In one embodiment, and after trench formation in a semiconductor substrate, the trench is filled with oxide to create a localized BOX. The top surface of the BOX is recessed to depth below the topmost surface of the semiconductor substrate to expose sidewall surfaces of the semiconductor substrate within each trench. A semiconductor material is then epitaxially grown from the exposed sidewall surfaces of the semiconductor substrate.

1 .- 6 . (canceled) 
     
     
         7 . A method of forming a semiconductor structure comprising:
 providing a patterned material stack having at least one opening on an upper surface of a semiconductor substrate;   forming at least one trench within the semiconductor substrate utilizing said patterned material stack as an etch mask;   forming a sacrificial nitride-containing spacer on each exposed sidewall of said patterned material stack and said semiconductor substrate, wherein a base of said sacrificial nitride-containing spacer is present on an exposed surface of said semiconductor substrate within a bottom portion of said at least one trench;   oxidizing said exposed portion of said semiconductor substrate at said bottom portion of said at least one trench, wherein said oxidizing forms a semiconductor oxide region within said semiconductor substrate at said bottom portion of said at least one trench;   removing the sacrificial nitride-containing spacer to expose sidewall surfaces of said semiconductor substrate within said at least one trench;   epitaxially growing a semiconductor material from said exposed sidewall surfaces, wherein said semiconductor material completely fills a remaining portion of the at least one trench and said at least one opening; and   removing the patterned material stack and said semiconductor material present above the upper surface of the semiconductor substrate and within said at least one opening.   
     
     
         8 . The method of  claim 7 , wherein said providing the patterned material stack comprises:
 forming a first pad oxide on the upper surface of the semiconductor substrate;   forming a first oxygen-impermeable layer on an exposed surface of said first pad oxide;   forming a second pad oxide on an exposed surface of said first oxygen-impermeable layer;   forming a second oxygen-impermeable layer on an exposed surface of said second pad oxide;   forming a photoresist material on an exposed surface of said second oxygen-impermeable layer;   patterning said photoresist material by lithography; and   transferring a pattern from said photoresist material into said first and second oxygen-impermeable layers and said first and second pad oxides.   
     
     
         9 . The method of  claim 7 , wherein said forming said at least one trench comprises forming a pair of trenches within said semiconductor substrate, wherein a first trench of said pair of trenches is separated from a second trench of said pair of trenches by a laterally isolation semiconductor material portion of said semiconductor substrate. 
     
     
         10 . The method of  claim 7 , wherein said semiconductor oxide region has a width that is greater than a width of said at least one trench. 
     
     
         11 . The method of  claim 7 , wherein said oxidizing comprises a thermal oxidation process. 
     
     
         12 . The method of  claim 7 , further comprising forming a bulk semiconductor device on an exposed surface of said semiconductor substrate which is adjacent said at least one trench including said semiconductor oxide and said semiconductor material, wherein said bulk semiconductor device is separated from said at least one trench by a trench isolation region. 
     
     
         13 .- 18 . (canceled) 
     
     
         19 . A method of forming a semiconductor structure comprising:
 providing a patterned material stack having at least one opening on an upper surface of a semiconductor substrate;   forming at least one trench within the semiconductor substrate utilizing said patterned material stack as an etch mask;   oxidizing exposed surfaces of said semiconductor substrate within at least one trench, wherein said oxidizing forms a semiconductor oxide region within said at least one trench;   removing said patterned material stack from said upper surface of said semiconductor substrate;   forming a pair of recessed regions within said semiconductor oxide region, wherein an oxide pillar portion separates one of said recessed regions from another of said recessed regions and wherein sidewall surfaces of said semiconductor substrate within are exposed;   epitaxially growing a semiconductor material from said exposed sidewall surfaces, wherein said semiconductor material completely fills each of said recessed regions; and   removing excess semiconductor material present above the upper surface of the semiconductor substrate.   
     
     
         20 . The method of  claim 19 , wherein said providing the patterned material stack comprises:
 forming a pad oxide on the upper surface of the semiconductor substrate;   forming an oxygen-impermeable layer on an exposed surface of said pad oxide;   forming a photoresist material on an exposed surface of said oxygen-impermeable layer;   patterning said photoresist material by lithography; and   transferring a pattern from said photoresist material into said oxygen-impermeable layer and said pad oxide.   
     
     
         21 . The method of  claim 19 , wherein said forming said at least one trench comprises forming a pair of trenches within said semiconductor substrate, wherein a first trench of said pair of trenches is separated from a second trench of said pair of trenches by a laterally isolation semiconductor material portion of said semiconductor substrate. 
     
     
         22 . The method of  claim 19 , wherein said forming said pair of recessed regions within said at least one trench comprises:
 forming an oxygen-impermeable layer on the upper surface of said semiconductor substrate including an uppermost surface of said semiconductor oxide region within said at least one trench;   forming a patterned photoresist on an exposed surface of said oxygen-impermeable layer, wherein a resist portion of said patterned photoresist is located atop a portion of said semiconductor oxide region within said at least one trench;   performing a controlled etching process; and   removing said patterned photoresist and remaining portions of said oxygen-impermeable layer.   
     
     
         23 . The method of  claim 19 , further comprising forming a bulk semiconductor device on an exposed surface of said semiconductor substrate which is adjacent said at least one trench including said semiconductor oxide and said semiconductor material, wherein said bulk semiconductor device is separated from said at least one trench by a trench isolation region.