Method to co-integrate SiGe and Si channels for finFET devices
View Patent ↗A method for co-integrating finFETs of two semiconductor material types, e.g., Si and SiGe, on a bulk substrate is described. Fins for finFETs may be formed in an epitaxial layer of a first semiconductor type, and covered with an insulator. A portion of the fins may be removed to form voids in the insulator, and the voids may be filled by epitaxially growing a semiconductor material of a second type in the voids. The co-integrated finFETs may be formed at a same device level.
1. A structure suitable for use in integrated circuits, the structure comprising:
a silicon substrate;
a first fin including
a lower portion in which a first semiconductor material extends vertically upward from an upper surface of the silicon substrate; and
an upper portion in which a second, epitaxially-grown, semiconductor material extends vertically upward from said lower portion, the second, epitaxially-grown, semiconductor material being different from the first semiconductor material; and
a second fin extending vertically upward from the upper surface of the silicon substrate and being epitaxially grown from the first semiconductor material.
2. The structure of claim 1 , wherein the first semiconductor material comprises Si and the second semiconductor material comprises SiGe.
3. The structure of claim 2 , further comprising an insulating layer abutting the first and second fins.
4. The structure of claim 1 , wherein the first finFET comprises a p-type finFET, and the second finFET comprises an n-type finFET.
5. The structure of claim 1 , wherein the first and second fins have a height between 10 nm and 100 nm.
6. The structure of claim 1 , wherein the first and second fins have a width between 5 nm and 50 nm.
7. The structure of claim 1 , wherein the first and second fins have approximately a same width and approximately a same top height.
8. The structure of claim 1 , wherein the first finFET comprises a plurality of first finFETs each having a respective first fin, and wherein the plurality of first fins are spaced laterally on regular spacing intervals.
9. The structure of claim 8 , wherein the second finFET comprises a plurality of second finFETs each having a respective second fin, and wherein the plurality of second fins are spaced laterally on regular spacing intervals.
10. A co-integrated finFET array, comprising:
a silicon substrate;
a plurality of n-type fins formed from the silicon substrate, each n-type fin including a source region, a drain region, and a channel extending between the source and drain regions;
a plurality of p-type fins co-integrated with the n-type fins on the silicon substrate, the p-type fins including a first portion that is formed from the substrate, the p-type fins being adjacent to, and aligned in a same direction as, the plurality of n-type fins, each p-type fin including a source region, a drain region, and a channel extending between the source and drain regions, the p-type fins including a second portion formed on the first portion, the second portion including a semiconductor material that is different from the substrate; and
a gate overlying the fins, the gate being oriented transverse to each of the pluralities of fins.
11. The finFET array of claim 10 wherein the second portions are epitaxially grown from first portions of the p-type fins.
12. The finFET array of claim 10 wherein the second portions are at least twice as tall as the first portions.
13. The finFET array of claim 11 wherein the lower portions are extensions of the substrate.
14. The finFET array of claim 10 wherein the fins are spaced apart from one another at regular, uniform, intervals.
15. The finFET array of claim 10 wherein the fins are spaced apart from one another at alternating intervals.