Field effect transistors with channels oriented to different crystal planes
View Patent ↗An integrated circuit includes a first field effect transistor of a first carrier type and a second field effect transistor of a second, different carrier type. In a conductive state, a first channel of the first field effect transistor is oriented to one of a first set of equivalent crystal planes of a semiconductor substrate and a second channel of the second field effect transistor is oriented to at least one of a second, different set of equivalent crystal planes. The first set of equivalent crystal planes is parallel to a main surface of the semiconductor substrate and the second set of equivalent crystal planes is perpendicular to the main surface.
1. An integrated circuit, comprising:
a first field effect transistor comprising a first channel oriented to one of a first set of equivalent crystal planes of a semiconductor substrate, the first set being parallel to a main surface of the semiconductor substrate; and
a second field effect transistor comprising a second channel at least a portion of which is oriented to a second set of parallel crystal planes of the semiconductor substrate, the second set being tilted with reference to the main surface, the second field effect transistor being separated from the first field effect transistor by an isolation structure in a first cross-section that is perpendicular to the main surface and that extends along a first direction extending between the first and second channels;
wherein the second channel is configured to provide a path for current flow between first and second source/drain regions of the second field effect transistor in a second direction perpendicular to the first cross-section and parallel to the intersection lines of the first and second sets of parallel crystal planes; and
wherein the first channel configured to provide a path for current flow between first and second source/drain regions of the first field effect transistor in the second direction such that the first and second channels are configured to provide paths for current flow along a same crystal axis but on crystal planes of different orientation.
2. The integrated circuit of claim 1 , wherein the second set of parallel crystal planes is tilted at an angle of 45 degrees to the main surface.
3. The integrated circuit of claim 1 , wherein the first field effect transistor is of a first carrier type and the second field effect transistor is of a second carrier type, the second carrier type being different from the first carrier type.
4. The integrated circuit of claim 1 , wherein the second channel comprises a further portion oriented to one of a third set of parallel crystal planes, the third set being equivalent to the second set and the channel portion extending along sidewalls of a V-shaped groove defined in the main surface.
5. The integrated circuit of claim 1 , wherein the main surface is oriented to a {100}-plane and the first field effect transistor is an n-channel field effect transistor.
6. The integrated circuit of claim 1 , wherein the main surface is oriented to a {111}-plane and the first field effect transistor is a p-channel field effect transistor.
7. The integrated circuit of claim 1 , wherein one of the first and second source/drain regions of the first field effect transistor is electrically coupled with one of the first and second source/drain regions of the second field effect transistor.
8. The integrated circuit of claim 1 , wherein the second field effect transistor comprises a FinFET.
9. The integrated circuit of claim 4 , wherein a gate electrode of the second field effect transistor is arranged in the V-shaped groove.
10. An integrated circuit, comprising:
a first field effect transistor comprising first and second source/drain regions and a first gate electrode disposed along a main surface of a semiconductor substrate adjacent to a first channel configured to provide a current flow path between the first and second source/drain regions in a direction of current flow; and
a second field effect transistor comprising first and second source/drain regions and a second gate electrode disposed in a groove disposed in the semiconductor substrate adjacent to a second channel configured to provide a current flow path between the first and second source/drain regions of the second field effect transistor in the direction of current flow, the groove comprising a first sidewall disposed along a first crystal plane and a second sidewall disposed along a second crystal plane in a cross-section extending along a first direction between the first and second gate electrodes;
wherein the direction of current flow in the first and second channels is perpendicular to the cross section extending along the first direction.
11. The integrated circuit of claim 10 , wherein the main surface is oriented to one of a first set of equivalent crystal planes comprising a (110)-crystal orientation and a (111)-crystal orientation and at least one sidewall of the groove is oriented to one of a second set of equivalent crystal planes, the second set of equivalent crystal planes being different from the first set of equivalent crystal planes.
12. The integrated circuit of claim 10 , wherein the first sidewall of the groove is tilted at an angle of 45 degrees in relation to the main surface.
13. The integrated circuit of claim 10 , wherein the main surface is oriented along a {111}-plane and the first field effect transistor is a p-channel field effect transistor.
14. The integrated circuit of claim 10 , wherein one of the first and second source/drain regions of the first field effect transistor is connected to one of the first and second source/drain regions of the second field effect transistor.
15. The integrated circuit of claim 10 , wherein the second field effect transistor comprises a FinFET.