Laser-induced structuring of substrate surfaces

Abstract

In one aspect, the present invention provides a method of processing a substrate, e.g., a semiconductor substrate, by irradiating a surface of the substrate (or at least a portion of the surface) with a first set of polarized short laser pulses while exposing the surface to a fluid to generate a plurality of structures on the surface, e.g., within a top layer of the surface. Subsequently, the structured surface can be irradiated with another set of polarized short laser pulses having a different polarization than that of the initial set while exposing the structured surface to a fluid, e.g., the same fluid initially utilized to form the structured surface or a different fluid. In many embodiments, the second set of polarized laser pulses cause the surface structures formed by the first set to break up into smaller-sized structures, e.g., nano-sized features such as nano-sized rods.

1 - 32 . (canceled) 
     
     
         33 . A semiconductor substrate, comprising:
 a plurality of nanosized structures disposed in a surface of the substrate, wherein said nanosized structures exhibit a surface density in a range of about 5×10 9  cm −2  to about 5×10 10  cm −2 .   
     
     
         34 . The semiconductor substrate of  claim 33 , wherein said substrate has a thickness in a range of about 1 micrometer to about 100 micrometers. 
     
     
         35 . The semiconductor of  claim 33 , wherein said substrate comprises a surface layer having a plurality of dopant inclusions, wherein said surface layer extends from said nanosized structures to a depth of the substrate. 
     
     
         36 . The semiconductor substrate of  claim 33 , wherein said nanosized structures have a height less than about 500 nm. 
     
     
         37 . The semiconductor substrate of  claim 33 , wherein said nanosized structures have a height in a range of about 50 nm to about 500 nm. 
     
     
         38 . The semiconductor substrate of  claim 33 , wherein said nanosized structures comprise a plurality of nanosized rods. 
     
     
         39 . The semiconductor substrate of  claim 33 , wherein said substrate comprises any of silicon, germanium, CdTe, CdSe or GaAs. 
     
     
         40 . The semiconductor substrate of  claim 33 , wherein said nanosized structures are formed by exposing the substrate to laser radiation. 
     
     
         41 . The semiconductor substrate of  claim 33 , wherein said laser radiation comprises a plurality of short radiation pulses. 
     
     
         42 . The semiconductor substrate of  claim 41 , wherein said short radiation pulses have a temporal duration in a range of about 10 fs to about a few hundred nanoseconds. 
     
     
         43 . The semiconductor substrate of  claim 42 , wherein said short radiation pulses have a temporal duration in a range of about 100 fs to about 1 ps. 
     
     
         44 . The semiconductor substrate of  claim 43 , wherein said short radiation pulses have a temporal duration in a range of about 100 fs to about 500 fs.