Semiconductor structure and method for its production

Abstract

The present invention relates to a semiconductor structure and a method for its production, the semiconductor structure comprising at least one conductor region 9 and at least two semiconductor regions ( 30,40 ), which semiconductor regions are partly separated by the at least one conductor region. The at least one conductor region comprises openings ( 22 ) extending between the semiconductor regions which are partly separated by the respective conductor region. The semiconductor regions comprise at least one organic semiconductor material having a specific HOMO energy level, in particular a DPP polymer. The conductor region comprises a conductive material having a specific work function, said combination of specific energy level and work function allowing for a simple preparation of the conductive region. The invention further relates to a method for providing such a semiconductor structure.

1 . A semiconductor structure, comprising:
 at least one conductor regions; and   at least two semiconductor regions, which are partly separated by the at least one conductor region,   wherein:   the at least one conductor region comprises openings extending between semiconductor regions which are partly separated by a respective conductor region;   at least one semiconductor region comprises a diketopyrrolopyrrole polymer as a semiconductor material;   the semiconductor regions comprise at least one organic semiconductor material having a highest occupied molecular orbital energy level E H , E H  being defined by:
   5.0 eV≦| E   H |≦5.8 eV; and
 
   the conductor region comprises a conductive material having a work function E C  by:
   | E   H |−1.5 eV≦| E   C   |≦|E   H |−0.4 eV.
 
   
     
     
         2 . The semiconductor structure of  claim 1 , wherein the organic semiconductor material has a bulk concentration of positive charge carrier equivalents N p  with N p ≦1×10 16  cm −3 , N p ≦8×10 15  cm −3 , N p ≦6×10 15  cm −3 , N p ≦5×10 15  cm −3 , N p ≦10 16  cm −3 , N p ≦4×10 15  cm −3 , N p ≦2×10 15  cm −3  , or N p ≦1×10 15  cm −3 . 
     
     
         3 . The semiconductor structure of  claim 2 , wherein E H , E C , and N p  are adapted to yield a depletion width I d  of more than 100 nm within the semiconductor region. 
     
     
         4 . The semiconductor structure of  claim 1 , wherein the at least one organic semiconductor material comprises a diketopyrrolopyrrole (DPP) polymer having one or more DPP skeletons represented by the following formula: 
       
         
           
           
               
               
           
         
       
       in the repeating unit,
 wherein: 
 R 1  and R 2  are the same or different from each other and are selected from the group consisting of hydrogen; a C 1 -C 100  alkyl group; —COOR 3 ; a C 1 -C 100  alkyl group which is substituted by one or more halogen atoms, hydroxyl groups, nitro groups, —CN, or C 6 -C 18  aryl groups and/or interrupted by —O—, —COO—, —OCO—, or —S—; a C 7 -C 100  arylalkyl group; a carbamoyl group; a C 5 -C 12  cycloalkyl group which can be substituted one to three times with a C 1 -C 8  alkyl group and/or a C 1 -C 8  alkoxy group; a C 6 -C 24  aryl group, and pentafluorophenyl; and 
 R 3  represents a C 1 -C 50  alkyl group. 
 
     
     
         5 . The semiconductor structure of  claim 4 , wherein the DPP polymer is selected from the group consisting of
 a polymer of formula (Ia):
   *A n *   (Ia),
 
   a copolymer of formula (Ib):
   *A-D n *   (Ib),
 
   a copolymer of formula (Ic):
   *A-D x B-D y  n *   (Ic), and
 
   and a copolymer of formula (Id):
   *A-D r B-D s A-E t B-E u  n *   (Id),
 
   wherein:   x=0.995 to 0.005;   y=0.005 to 0.995, with the proviso that x+y=1;   r=0.985 to 0.005;   s=0.005 to 0.985;   t=0.005 to 0.985;   u=0.005 to 0.985, with the proviso that r+s+t+u=1;   n=4 to 1000;   A is a group of formula (X):   
       
         
           
           
               
               
           
         
         wherein 
         a′=1, 2, or 3; 
         a″=0, 1, 2, or 3; 
         b=0, 1, 2, or 3; 
         b′=0, 1, 2, or 3; 
         c=0, 1, 2, or 3; 
         c′=0, 1, 2, or 3; 
         d=0, 1, 2, or 3; 
         d′=0, 1, 2, or 3; 
         with the proviso that b′ is not 0 if a″ is 0; 
         Ar 1 , Ar 1′ , Ar 2 , Ar 2′ , Ar 3 , Ar 3′ , Ar 4  and Ar 4′  are independently of each other heteroaromatic or aromatic rings, which optionally can be condensed and/or substituted; 
         D is —CO—, —COO—, —S—, —O—, or —NR 112 —; 
         E is C 1 -C 8  thioalkoxy, C 1 -C 8  alkoxy, CN, —NR 112 R 113 , —CONR 112 R 113 , or halogen, 
         R 112  and R 113  are independently of each other H; C 6 -C 18  aryl; C 6 -C 18  aryl which is substituted by C 1 -C 18  alkyl, or C 1 -C 18  alkoxy; C 1 -C 18  alkyl; or C 1 -C 18  alkyl which is interrupted by —O—; 
         B, D and E are independently of each other a group of formula:
   *Ar 4  k   Ar   5  l Ar 6  r Ar 7  z *,
 
 
       
       or formula (X), with the proviso that in case B, D and E are a group of formula (X), they are different from A, wherein k=1; l=0 or 1; r=0 or 1; z=0 or 1;
 Ar 4 , Ar 5 , Ar 6  and Ar 7  are independently of each other a group of formula: 
 
       
         
           
           
               
               
           
         
         wherein one of X 5  and X 6  is N and the other is CR 14 ; and 
         R 14 , R 14′ , R 17  and R 17′  are independently of each other H, or a C 1 -C 25  alkyl group, which may optionally be interrupted by one or more oxygen atoms. 
       
     
     
         6 . The semiconductor structure of  claim 5 , wherein the DPP polymer is a polymer according to formula (Ib-1), (Ib-9), (Ib-10): 
       
         
           
           
               
               
           
         
         wherein: 
         R 1  and R 2  are independently from each other a C 8 -C 36  alkyl group; and 
         n=4 to 1000. 
       
     
     
         7 . The semiconductor material of  claim 1 , wherein the organic semiconductor material has a polydispersity in the range of from 1.01 to 10. 
     
     
         8 . The semiconductor structure of  claim 1 , wherein the openings comprised in the conductor region have an inner width of more than 200 nm. 
     
     
         9 . The semiconductor structure of  claim 1 , wherein the conductive material of the conductor region comprises a metal, an alloy, or a conductive polymer. 
     
     
         10 . The semiconductor structure of  claim 1 , further comprising at least two electrodes at end faces of the semiconductor regions, wherein the electrodes as well as the conductor region each comprise a contact region or are provided with a conductor adapted for external contact. 
     
     
         11 . The semiconductor structure of  claim 1 , wherein:
 the semiconductor regions which are partly separated by the respective conductor region are in direct contact with each other through the openings of said conductor region; and   the semiconductor regions are separated by the respective conductor region by sections of the respective conductor region, which sections are lateral to the openings.   
     
     
         12 . The semiconductor structure of  claim 1 , comprising a conductor region partly separating two semiconductor regions,
 wherein:   the conductor region and the two semiconductor regions provide a vertical transistor structure; and   the conductor region provides a gate adapted for conductivity control between the semiconductor regions.   
     
     
         13 . A semiconductor structure, comprising:
 at least one conductor region:, and   at least two semiconductor regions, which are partly separated by the at least one conductor region,   wherein:   the at least one conductor region comprises openings extending between the semiconductor regions which are partly separated by the respective conductor region;   the semiconductor regions comprise at least one organic semiconductor material which is at least one DPP polymer; and   the conductor region comprises a metal selected from the group consisting of Al, Cr, Cu, Fe, In, Sb, Si, Sn, and Zn.   
     
     
         14 . A method for producing the semiconductor structure of  claim 1 , the method comprising
 partly contacting the at least two semiconductor regions through the openings of the at least one conductor region.   
     
     
         15 . The method of  claim 14 , further comprising embossing, mechanically cutting, or laser cutting the openings with an inner width of more than 200 nm through a continuous layer, wherein the at least one conductor region is the continuous layer of the conductive material.