Method and apparatus for an integrated laser beam scanner

Abstract

A solid state laser beam scanning system having a single crystal silicon deflection and scanning mirror integrated with a laser diode. By combining the techniques of deep reactive ion etching of silicon with solder bump bonding techniques, completed and tested laser diodes are integrated with silicon substrates supporting micro-electro-mechanical systems layers.

1. An integrated laser beam scanning structure comprising:
 a wafer having a recess on a side;  
 a layer having a first region and a second region, said layer being attached to said side of said wafer having said recess;  
 a deflecting mirror fashioned from said first region of said layer;  
 a torsional mirror fashioned from said second region of said layer, said torsional mirror having a first side; and  
 a semiconductor light emitter mounted in said recess whereby a light beam emitted from said semiconductor light emitter is deflected by said deflecting mirror onto said first side of said torsional mirror.  
 
     
     
       2. The structure of  claim 1  wherein said wafer is a silicon on oxide wafer. 
     
     
       3. The structure of  claim 1  wherein said layer is a single crystal silicon layer. 
     
     
       4. The structure of  claim 1  wherein said semiconductor light emitter is mounted in said recess using solder bumps. 
     
     
       5. The structure of  claim 1  wherein said semiconductor light emitter is a VCSEL chip. 
     
     
       6. The structure of  claim 1  wherein said recess is deep reactive ion etched. 
     
     
       7. The structure of  claim 1  wherein said torsional mirror is actuated by a pair of electrodes. 
     
     
       8. The structure of  claim 1  wherein a ferromagnetic thin film is attached to said first side of said torsional mirror. 
     
     
       9. The structure of  claim 8  wherein said torsional mirror is actuated by a thin film coil. 
     
     
       10. The structure of  claim 1  wherein a thin film coil is attached to said first side of said torsional mirror. 
     
     
       11. A method for making an integrated laser beam scanner comprising the steps of:
 providing a wafer having a recess on a side;  
 attaching a layer having a first region and a second region to said side of said wafer having said recess;  
 fashioning a deflecting mirror from said first region of said layer;  
 fashioning a torsional mirror from said second region of said layer, said torsional mirror having a first side; and  
 mounting a semiconductor light emitter in said recess such that a light beam emitted from said semiconductor light emitter is deflected by said deflecting mirror onto said first side of said torsional mirror.  
 
     
     
       12. The method of  claim 11  wherein said wafer is a silicon on oxide wafer. 
     
     
       13. The method of  claim 11  wherein said layer is a single crystalline silicon layer. 
     
     
       14. The method of  claim 11  wherein said semiconductor light emitter is mounted in said recess using solder bumps. 
     
     
       15. The method of  claim 11  wherein said semiconductor light emitter is a VCSEL chip. 
     
     
       16. The method of  claim 11  wherein said recess is deep reactive ion etched. 
     
     
       17. The method of  claim 11  wherein said torsional mirror is actuated by a pair of electrodes. 
     
     
       18. The method of  claim 11  wherein said torsional mirror is actuated by a thin film coil and an external magnetic field. 
     
     
       19. The method of  claim 11  wherein a ferromagnetic thin film is attached to said first side of said torsional mirror. 
     
     
       20. The method of  claim 11  wherein a thin film coil is attached to said first side of said torsional mirror. 
     
     
       21. A MEMS formation method including:
   providing a SOI wafer including a single crystal silicon layer attached to an insulator layer;        forming at least one first MEMS component by paterning the single crystal silicon layer;        depositing at least one layer of polysilicon on the patterned single crystal silicon; and        forming at least one second MEMS component by patterning the polysilicon.     
     
     
       22. The method of  claim 21  wherein the at least one second MEMS component is a hinge. 
     
     
       23. The method of  claim 22  wherein the at least one first MEMS component is a mirror retained by the hinge. 
     
     
       24. The method of  claim 21  wherein depositing at least one layer of polysilicon includes chemical vapor deposition. 
     
     
       25. The method of  claim 24  wherein depositing at least one layer of polysilicon includes low pressure chemical vapor deposition. 
     
     
       26. A MEMS formation method including:
   providing a SOI wafer including a single crystal silicon layer attached to an insulated layer;        forming at least one first MEMS component by patterning the single crystal silicon layer;        depositing at least one layer of polysilicon on the patterned single crystal silicon; wherein forming at least one first MEMS component includes forming a deflecting mirror, and forming at least one second MEMS component by patterning the polysilicon, the at least one second MEMS component including a hinge retaining the deflecting mirror.     
     
     
       27. The method of  claim 26  wherein forming at least one first MEMS component further includes forming a torsional mirror, and the method further comprises forming a recess in the SOI wafer and mounting a light emitter in the recess so that it will emit light at the deflecting mirror, which deflects light to the torsional mirror. 
     
     
       28. A MEMS device comprising:
   at least one single crystal silicon component bonded to an insulator that rests on a handle wafer; and        a polysilicon hinge derived from a layer of polysilicon applied over the at least one single crystalline component.     
     
     
       29. The MEMS device of  claim 28  wherein the at least one single crystal silicon component comprises a deflecting mirror retained by the hinge. 
     
     
       30. The MEMS device of  claim 28  wherein the at least one single crystal silicon component comprises a torsional mirror. 
     
     
       31. A MEMS device comprising:
   at least one single crystal silicon component bonded to an insulator that rests on a handle wafer; and        at least one polysilicon component derived from a layer of polysilicon applied over the at least one single crystalline silicon component;        a recess in the handle wafer aligned with the at least one single crystal silicon component; and        a semiconductor light emitter mounted in the recess to emit a light beam at the single crystal silicon component.     
     
     
       32. The MEMS device of  claim 31  wherein the at least one single crystal silicon component comprises a deflecting mirror at which the light beam is directed and a torsional mirror to which the deflecting mirror deflects the light beam, and the at least one polysilicon component comprises a hinge retaining the deflecting mirror.