Method of making a multiple crystal orientation semiconductor device
View Patent ↗A method of having transistors formed in enhanced performance crystal orientations begins with a wafer having a semiconductor substrate ( 12,52 ) of a first surface orientation, a thin etch stop layer ( 14,54 ) on the semiconductor substrate, a buried oxide layer ( 16,56 ) on the thin etch stop layer, and a semiconductor layer ( 18,58 ) of a second surface orientation on the buried oxide layer. An etch penetrates to the thin etch stop layer. Another etch, which is chosen to minimize the damage to the underlying semiconductor substrate, exposes a portion of the semiconductor substrate. An epitaxial semiconductor ( 28,66 ) is then grown from the exposed portion of the semiconductor substrate to form a semiconductor region having the first surface orientation and having few, if any, defects. The epitaxially grown semiconductor region is then used for enhancing one type of transistor while the semiconductor layer of the second surface orientation is used for enhancing a different type of transistor.
1. A method of making a semiconductor device structure, comprising:
providing a semiconductor substrate comprising:
a first semiconductor layer having a first surface orientation;
a first dielectric layer over the first semiconductor layer, wherein the first dielectric layer comprises a high K dielectric;
a second dielectric layer over the first dielectric layer; and
a second semiconductor layer over the second dielectric layer, wherein the second semiconductor layer has a second surface orientation;
performing a patterned etch through the second semiconductor layer and the second dielectric layer to form an opening in the second semiconductor layer and the second dielectric layer, wherein:
the patterned etch is stopped on the first dielectric layer; and
the patterned etch comprises a first etch type;
etching through the first dielectric layer to the first semiconductor layer using a second etch type whereby the first semiconductor layer has an exposed portion at the opening;
epitaxially growing a semiconductor region of the first surface orientation from the exposed portion into the opening;
forming a transistor of the first type in the semiconductor region;
forming a transistor of the second type in the second semiconductor layer.
2. The method of claim 1 , wherein:
the first dielectric layer has a first thickness;
the second dielectric layer has a second thickness; and
the second thickness is at least five times greater than the first thickness.
3. The method of claim 1 , wherein the second etch type comprises a hot gas that contains chlorine.
4. The method of claim 3 , wherein the second etch type is further characterized as being hydrochloric acid.
5. The method of claim 4 , wherein the second etch type is further characterized as applying the hot gas at a temperature of at least 500 degrees Celsius.
6. The method of claim 1 , wherein the second etch type etches the first dielectric layer at a significantly greater rate than the first semiconductor layer, the second dielectric layer, and the second semiconductor layer.
7. The method of claim 1 , further comprising, prior to the step of etching through the first dielectric layer, the following steps:
filling the opening with an insulating material; and
pattern etching through the insulating material to leave a portion of the insulating material along a perimeter of the opening for providing isolation between the first transistor and the second transistor.
8. The method of claim 1 , further comprising forming an antireflective coating over the insulating material prior to pattern etching through the insulating material.
9. The method of claim 1 , further comprising:
forming a sidewall spacer along a perimeter of the opening prior to the step of etching through the first dielectric layer;
removing at least a first portion of the sidewall spacer; and
forming an isolation region where the first portion of the sidewall spacer was removed.
10. The method of claim 1 , wherein the first surface orientation comprises ( 110 ), the second surface orientation comprises ( 100 ), the first type of transistor comprises P channel, the second type of transistor comprises N channel, and the first semiconductor region is of a different material composition from the first semiconductor layer.
11. A method of forming a semiconductor device structure, comprising:
providing a semiconductor substrate comprising:
a first semiconductor layer having a first crystal orientation;
a first dielectric layer over the first semiconductor layer;
a second dielectric layer over the first dielectric layer, wherein the first dielectric layer comprises a high K dielectric layer that is at least five times thicker than the second dielectric layer; and
a second semiconductor layer over the second dielectric layer, wherein the second semiconductor layer has a second crystal orientation;
etching through the second semiconductor layer and the second dielectric layer whereby the first dielectric layer has an exposed portion;
etching through the first dielectric layer whereby the first semiconductor layer has an exposed portion; and
epitaxially growing a semiconductor region from the exposed portion of the first semiconductor layer.
12. The method of claim 11 , wherein:
the etching through the second dielectric layer comprises applying a fluorine-containing gas; and
the step of etching through the first dielectric layer comprises applying a chlorine-containing gas at temperature of at least 500 degrees Celsius.
13. The method of claim 11 , further comprising
forming a first transistor in the semiconductor region; and
forming a second transistor in the second semiconductor layer, wherein the second transistor is a different type from the first transistor.
14. The method of claim 11 , wherein the first crystal orientation is a surface orientation of ( 110 ) and the second crystal orientation is a surface of orientation of ( 100 ).
15. The method of claim 11 , further comprising, after etching through the second dielectric layer and prior to etching through the first dielectric layer, the following steps:
depositing an insulating material; and
pattern etching through the insulating material to the first dielectric layer to leave an opening through the insulating material for the exposed portion of the first insulating layer.
16. A method of forming a semiconductor device structure, comprising:
providing a semiconductor substrate comprising:
a first semiconductor layer having a first crystal orientation;
a first dielectric layer over the first semiconductor layer;
a second dielectric layer over the first dielectric layer; and
a second semiconductor layer over the second dielectric layer, wherein the second semiconductor layer has a second crystal orientation;
etching through the second semiconductor layer and the second dielectric layer whereby the first dielectric layer has an exposed portion;
etching through the first dielectric layer whereby the first semiconductor layer has an exposed portion; and
epitaxially growing a semiconductor region from the exposed portion of the first semiconductor layer, wherein the step of etching through the second semiconductor layer and the second dielectric layer leaves an opening, further comprising:
forming a sidewall spacer along a perimeter of the opening prior to the step of etching through the first dielectric layer;
removing at least a first portion of the sidewall spacer; and
forming an isolation region where the first portion of the sidewall spacer was removed.