Creation of wide band gap material for integration to SOI thereof
Devices and methods for forming a device are presented. The method for forming the device includes providing a support substrate having first crystal orientation. A trap rich layer is formed on the support substrate. An insulator layer is formed over a top surface of the trap rich layer. The method further includes forming a top surface layer having second crystal orientation on the insulator layer. The support substrate, the trap rich layer, the insulator layer and the top surface layer correspond to a substrate and the substrate is defined with at least first and second device regions. A transistor is formed in the top surface layer in the first device region and a wide band gap device is formed in the second device region.
1. A method for forming a device comprising:
providing a support substrate having first crystal orientation;
forming a trap rich layer on the support substrate;
forming an insulator layer over a top surface of the trap rich layer;
forming a top surface layer having second crystal orientation on the insulator layer, wherein the support substrate, the trap rich layer, the insulator layer and the top surface layer correspond to a substrate and the substrate is defined with at least first and second device regions, and wherein the first and second device regions are separated by first isolation regions;
forming a transistor in the top surface layer in the first device region; and
forming a wide band gap device in the second device region, wherein the wide band gap device in the second device region is formed through a second isolation region in the second device region.
2. The method of claim 1 wherein the support substrate comprises a <111> oriented single crystal substrate and the top surface layer comprises a <100> oriented single crystal substrate.
3. The method of claim 2 wherein the trap rich layer is formed by growing a layer of wide band gap material on top of the support substrate.
4. The method of claim 3 wherein the trap rich layer is formed using nano-crystal Si or wide band gap materials which comprise GaN, AlGaN, GaAs or SiC.
5. The method of claim 1 wherein the first isolation regions extends to a top surface of the insulator layer.
6. A method for forming a device comprising:
providing a support substrate having first crystal orientation;
forming a trap rich layer on the support substrate;
forming an insulator layer over a top surface of the trap rich layer;
forming a top surface layer having second crystal orientation on the insulator layer, wherein the support substrate, the trap rich layer, the insulator layer and the top surface layer correspond to a substrate and the substrate is defined with at least first and second device regions, and wherein the first device region and second device region are separated by first isolation regions extending to a top surface of the insulator layer;
forming a transistor in the top surface layer in the first device region; and
forming a wide band gap device in the second device region, wherein the wide band gap device in the second device region is formed through a second isolation region in the second device region, the second isolation region having a greater width than the first isolation regions.
7. The method of claim 6 comprising forming an etch stop layer over the top surface layer to enable etching of a portion of the second isolation region in the second device region to form an opening which exposes the insulator layer and a portion of the trap rich layer in the second device region.
8. The method of claim 7 , wherein the etching of a portion of the second isolation region leaves remaining portions of the second isolation region in the second device region to isolate the wide band gap device from the top surface layer, thereby preventing electrical shorts.
9. The method of claim 7 wherein the second isolation region and the insulator layer are formed by the same material.
10. The method of claim 7 further comprising:
forming a protective layer on both the first and second device regions, the protective layer covering the transistor in the first device region and also sidewalls and bottom of the opening; and
removing a portion of the protective layer above the trap rich layer so that the protective layer only covers the sidewalls of the opening in the second device region.
11. A method for forming a device comprising:
providing a support substrate having first crystal orientation;
forming a trap rich layer on the support substrate;
forming an insulator layer over a top surface of the trap rich layer;
forming a top surface layer having second crystal orientation on the insulator layer, wherein the support substrate, the trap rich layer, the insulator layer and the top surface layer correspond to a substrate and the substrate is defined with at least first and second device regions;
forming a transistor in the top surface layer in the first device region;
forming a wide band gap device in the second device region; and
forming protective layers in the second device region, wherein the protective layers isolate materials of the wide band gap device from materials of the substrate.
12. The method of claim 11 wherein the support substrate comprises a <111> oriented single crystal substrate and the top surface layer comprises a <100> oriented single crystal substrate.
13. The method of claim 11 wherein the trap rich layer is formed by polysilicon deposition and temperature treatment prior to forming the insulator layer.
14. The method of claim 13 wherein the first device region and second device region are separated by first isolation regions extending to a top surface of the insulator layer.
15. The method of claim 14 wherein the wide band gap device in the second device region is formed through a second isolation region in the second device region, the second isolation region having a greater width than the first isolation regions.
16. The method of claim 15 comprising forming an etch stop layer over the top surface layer to enable etching of a portion of the second isolation region in the second device region to form an opening which exposes the insulator layer, the trap rich layer and a portion of the support substrate in the second device region.
17. The method of claim 16 , wherein the etching of a portion of the second isolation region leaves remaining portions of the second isolation region in the second device region to isolate the wide band gap device from the top surface layer, thereby preventing electrical shorts.
18. The method of claim 17 wherein the protective layers cover sidewalls of the opening and extend from a top surface of the top surface layer towards a top surface of the support substrate.
19. The method of claim 11 wherein the wide band gap device in the second device region comprises a High Electron Mobility Transistor (HEMT) or Hetero-junction Bipolar Transistor (HBT) device.
20. The method of claim 11 wherein the protective layers extend from a top surface of the top surface layer towards a top surface of the trap rich layer.