Using different gate dielectrics with NMOS and PMOS transistors of a complementary metal oxide semiconductor integrated circuit

Abstract

Complementary metal oxide semiconductor integrated circuits may be formed with NMOS and PMOS transistors having different gate dielectrics. The different gate dielectrics may be formed, for example, by a replacement process. The gate dielectrics may differ in material, thickness, or formation techniques, as a few examples.

1 . an integrated circuit comprising: 
 a substrate; and    an NMOS transistor and a PMOS transistor, said NMOS and PMOS transistors formed on said substrate, said NMOS transistor and said PMOS transistor forming a complementary metal oxide semiconductor structure, said NMOS transistor and said PMOS transistor having different gate dielectrics, one of said transistors having a gate dielectric with a dielectric constant greater than 10 and the other of said transistors having a gate dielectric with a dielectric constant of less than 10.    
   
   
       2 . The circuit of  claim 1  wherein said dielectrics have different dielectric thicknesses.  
   
   
       3 . The circuit of  claim 1  wherein said dielectrics are formed of different dielectric materials.  
   
   
       4 . The circuit of  claim 1  wherein said dielectrics are formed by different techniques.  
   
   
       5 . The circuit of  claim 1  wherein said dielectrics are covered by metal gate electrodes.  
   
   
       6 . The circuit of  claim 1  wherein said NMOS transistor has a gate dielectric with a larger conduction band offset.  
   
   
       7 . The circuit of  claim 1  wherein said PMOS transistor has a gate dielectric with a higher dielectric constant.  
   
   
       8 . The circuit of  claim 1  wherein the gate dielectric of said NMOS transistor is thicker than the gate dielectric of said PMOS transistor.