Semiconductor substrate of GaAs and semiconductor device

Abstract

A semiconductor substrate ( 1 ) of GaAs with a semiconductor layer sequence ( 2 ) applied on top. The semiconductor layer sequence ( 2 ) contains a plurality of semiconductor layers ( 3, 4, 5, 6, 7 ) of Al 1−y Ga y As 1−x Px with 0≦x≦1 and 0≦y≦1, the phosphorus component x in a number of the semiconductor layers respectively being greater than in a neighboring semiconductor layer lying thereunder in the direction of growth. Such a semiconductor substrate may be advantageously used as a quasi-substrate substrate ( 8 ) for growing further semiconductor layers ( 28 ) which have a smaller lattice constant than GaAs.

1 . A semiconductor substrate of GaAs with a semiconductor layer sequence applied on top, wherein the semiconductor layer sequence contains a plurality of semiconductor layers of Al 1−y Ga y As 1−x P x  with 0≦x≦1 and 0≦y≦1, a number of the semiconductor layers respectively having a phosphorus component x which is greater than in a neighboring semiconductor layer lying thereunder in the direction of growth of the semiconductor layer sequence.  
   
   
       2 . The semiconductor substrate as claimed in  claim 1 , wherein the phosphorus component x in at least 2 semiconductor layers of the semiconductor layer sequence is greater than in a neighboring semiconductor layer lying thereunder in the direction of growth of the semiconductor layer sequence.  
   
   
       3 . The semiconductor substrate as claimed in  claim 1 , wherein the phosphorus component x increases stage by stage in a number of successive semiconductor layers of the semiconductor layer sequence.  
   
   
       4 . The semiconductor substrate as claimed in  claim 3 , wherein the phosphorus component x increases stage by stage in at least 3 successive semiconductor layers of the semiconductor layer sequence.  
   
   
       5 . The semiconductor substrate as claimed in  claim 1 , wherein the semiconductor layer sequence includes a superlattice structure comprising alternating first semiconductor layers and second semiconductor layers, the first semiconductor layers containing a phosphorus component x 1 ≧0 and the second semiconductor layers containing a phosphorus component x 2 ≧0 with x 1 ≠x 2 .  
   
   
       6 . The semiconductor substrate as claimed in  claim 1 , for the phosphorus component x in the uppermost semiconductor layer of the semiconductor layer sequence, x≧0.15.  
   
   
       7 . The semiconductor substrate as claimed in  claim 1 , wherein, for the aluminum component 1−y in the semiconductor layer sequence, 1−y=0.  
   
   
       8 . The semiconductor substrate as claimed in  claim 1 , wherein the overall thickness of the semiconductor layer sequence is 10 μm or less.  
   
   
       9 . The semiconductor substrate as claimed in  claim 1 , wherein the semiconductor layers have a thickness of between 100 nm and 1000 nm, inclusive.  
   
   
       10 . The semiconductor substrate as claimed in  claim 1 , wherein the uppermost semiconductor layer of the semiconductor layer sequence has a smaller lattice constant than the GaAs substrate.  
   
   
       11 . The semiconductor substrate as claimed in  claim 1 , wherein the uppermost semiconductor layer of the semiconductor layer sequence has a smaller lattice constant than at least one of the preceding semiconductor layers.  
   
   
       12 . The semiconductor substrate as claimed in  claim 11 , wherein the uppermost semiconductor layer of the semiconductor layer sequence has a smaller lattice constant than the two semiconductor layers preceding it.  
   
   
       13 . The semiconductor substrate as claimed in  claim 1 , wherein at least one semiconductor layer of the semiconductor layer sequence is relaxed.  
   
   
       14 . The semiconductor substrate as claimed in  claim 13 , wherein the uppermost semiconductor layer of the semiconductor layer sequence is relaxed.  
   
   
       15 . A semiconductor device, wherein the semiconductor contains a GaAs substrate with a semiconductor layer sequence as claimed in  claim 1  applied on top.  
   
   
       16 . The semiconductor device as claimed in  claim 15 , wherein the semiconductor device is an optoelectronic device.  
   
   
       17 . The semiconductor device as claimed in  claim 16 , wherein the optoelectronic device is a luminescence diode or a semiconductor laser.  
   
   
       18 . The semiconductor device as claimed in  claim 16 , wherein the optoelectronic device contains a radiation-detecting or radiation-emitting layer.  
   
   
       19 . The semiconductor device as claimed in  claim 18 , wherein the radiation-detecting or radiation-emitting layer contains In x Al y Ga 1−x−y P with 0≦x<0.5, 0≦y≦1 and x+y≦1.  
   
   
       20 . The semiconductor device as claimed in  claim 18 , wherein the radiation-detecting or radiation-emitting layer contains ZnSSe or ZnMgSSe.  
   
   
       21 . The semiconductor device as claimed in  claim 18 , wherein the radiation-detecting or radiation-emitting layer contains GaAsN or InGaAsN.  
   
   
       22 . The semiconductor device as claimed in  claim 18 , wherein the radiation-detecting or radiation-emitting layer is included in a further semiconductor layer sequence, which is epitaxially grown on the semiconductor layer sequence.