Formation of common interfacial layer on Si/SiGe dual channel complementary metal oxide semiconductor device
A method is presented for forming a semiconductor structure. The method includes forming a silicon (Si) channel for a first device, forming a first interfacial layer over the Si channel, forming a silicon-germanium (SiGe) channel for a second device, forming a second interfacial layer over the SiGe channel, and selectively removing germanium oxide (GeO X ) from the second interfacial layer by applying a combination of hydrogen (H 2 ) and hydrogen chloride (HCl). The second interfacial is silicon germanium oxide (SiGeO X ) and removal of the GeO X results in formation of a pure silicon dioxide (SiO 2 ) layer.
1. A method for forming a semiconductor structure, the method comprising:
forming a first channel for a first device;
forming a first interfacial layer in direct contact with the first channel;
forming a second channel for a second device;
forming a second interfacial layer in direct contact with the second channel, where the first interfacial layer is constructed from a different material than the second interfacial layer; and
selectively removing germanium oxide (GeO X ) from the second interfacial layer by applying a combination of gases to convert the first interfacial layer to have a same chemical compound as the second interfacial layer; and
depositing a high-k metal gate in direct contact with the converted first interfacial layer.
2. The method of claim 1 , wherein the first device is an n-type field effect transistor (nFET).
3. The method of claim 1 , wherein the second device is a p-type field effect transistor (pFET).
4. The method of claim 1 , wherein the first channel is silicon (Si), the second channel is silicon germanium (SiGe), and the second interfacial is silicon germanium oxide (SiGeO X ).
5. The method of claim 1 , wherein removal of the GeO X results in formation of a pure silicon dioxide (SiO 2 ) layer.
6. The method of claim 1 , wherein the converted first interfacial layer is formed between spacers.
7. The method of claim 6 , wherein the combination of gases are applied to sidewalls of the spacers before the converted first interfacial layer is formed.
8. The method of claim 1 , wherein removal of the GeO X prevents breaking of Si—O bonds in the second interfacial layer.
9. The method of claim 1 , wherein removal of the GeO X results in decreased interface trap density in the second interfacial and the second channel.
10. The method of claim 1 , wherein the gases are a combination of hydrogen (H 2 ) and hydrogen chloride (HCl).