Hybrid crystallographic surface orientation substrate having one or more soi regions and/or bulk semiconductor regions

Abstract

A substrate for a semiconductor device is disclosed including, in one embodiment, a plurality of semiconductor-on-insulator (SOI) wafers bonded to one another in a single stack. A distal end of the stack includes a first SOI region with a first semiconductor layer having a thickness and a first surface orientation. A surface of the single stack may further include a non-SOI region and/or at least one second SOI region. The non-SOI region may include bulk silicon that extends through all of the insulator layers of the single stack and has a thickness different than that of the first silicon layer. Each second SOI region has a second semiconductor layer having a thickness different than that of the first semiconductor layer and/or a different surface orientation than the first surface orientation. The substrate thus allows formation of different devices on optimal substrate regions that may include different surface orientations and/or different thicknesses and/or different bulk or SOI structures.

1 . A method of forming a semiconductor substrate, the method comprising the steps of: 
 providing a first semiconductor-on-insulator (SOI) wafer;    bonding a second SOI wafer to the first SOI wafer;    forming an opening through a distal semiconductor surface of the bonded wafers, the opening extending to expose one of the other semiconductor layers of the SOI wafers;    forming an isolation in the opening; and    re-growing a semiconductor material in the opening, the semiconductor material having the same surface orientation as the exposed semiconductor layer.    
   
   
       2 . The method of  claim 1 , wherein the opening extends through all insulator layers of the SOI wafers and the semiconductor material includes a bulk silicon.  
   
   
       3 . The method of  claim 1 , further comprising the step of forming another opening to a different semiconductor layer of the SOI wafers, and repeating the isolation forming and re-growing steps for the another opening.  
   
   
       4 . The method of  claim 3 , wherein at least one re-grown semiconductor material has a surface orientation different than a surface orientation of the distal semiconductor surface.  
   
   
       5 . The method of  claim 1 , wherein the bonding step includes forming an oxidized insulator layer on a surface of the second SOI wafer and joining the first and second SOI wafers at the oxidized insulator layer.