Semiconductor-on-insulator (SOI) device and related methods for making same using non-oxidizing thermal treatment
A method for making a semiconductor device may include forming, on a first semiconductor layer of a semiconductor-on-insulator (SOI) wafer, a second semiconductor layer comprising a second semiconductor material different than a first semiconductor material of the first semiconductor layer. The method may further include performing a thermal treatment in a non-oxidizing atmosphere to diffuse the second semiconductor material into the first semiconductor layer, and removing the second semiconductor layer.
1. A method for making a semiconductor device comprising:
forming, on a first semiconductor layer of a semiconductor-on-insulator (SOI) wafer, a second semiconductor layer comprising a second semiconductor material different than a first semiconductor material of the first semiconductor layer;
forming a nitride layer overlying the second semiconductor layer;
after forming the nitride layer, performing a thermal treatment in a non-oxidizing atmosphere to diffuse the second semiconductor material into the first semiconductor layer to provide a non-linear diffusion profile of the second semiconductor material within the first semiconductor layer with a given concentration of the second semiconductor material at an interface between the first and second semiconductor layers; and
removing the nitride layer and etching a remainder of the second semiconductor layer after performing the thermal treatment using an etchant corresponding to the given concentration at the interface.
2. The method of claim 1 wherein etching the remainder of the second semiconductor layer comprises removing the remainder of the second semiconductor layer using a wet etch.
3. The method of claim 1 wherein performing the thermal treatment comprises performing the thermal treatment in the non-oxidizing atmosphere for 50 seconds or less.
4. The method of claim 1 wherein performing the thermal treatment comprises performing the thermal treatment in the non-oxidizing atmosphere at a temperature of 1000° C. or less.
5. The method of claim 1 wherein the second semiconductor material comprises germanium, and the first semiconductor material comprises silicon.
6. The method of claim 1 further comprising forming source and drain regions defining a channel in the first semiconductor layer after the diffusion of the second semiconductor material therein, and forming a gate above the channel.
7. The method of claim 1 wherein the SOI wafer comprises an ultra-thin body and buried oxide (UTBB) wafer.
8. A method for making a semiconductor device comprising:
forming, on a first semiconductor layer of a semiconductor-on-insulator (SOI) wafer, a second semiconductor layer comprising a second semiconductor material different than a first semiconductor material of the first semiconductor layer;
forming a nitride layer overlying the second semiconductor layer;
after forming the nitride layer, performing a thermal treatment in a non-oxidizing atmosphere to provide a non-linear diffusion profile of the second semiconductor material within the first semiconductor layer with a given concentration of the second semiconductor material at an interface between the first and second semiconductor layers; and
removing the nitride layer and etching a remainder of the second semiconductor layer after performing the thermal treatment using a wet etch corresponding to the given concentration at the interface.
9. The method of claim 8 wherein performing the thermal treatment comprises performing the thermal treatment in the non-oxidizing atmosphere for 50 seconds or less.
10. The method of claim 8 wherein performing the thermal treatment comprises performing the thermal treatment in the non-oxidizing atmosphere at a temperature of 1000° C. or less.
11. The method of claim 8 wherein the second semiconductor material comprises germanium, and the first semiconductor material comprises silicon.
12. A method for making a semiconductor device comprising:
forming, on a first semiconductor layer of a semiconductor-on-insulator (SOI) wafer, a second semiconductor layer comprising a second semiconductor material different than a first semiconductor material of the first semiconductor layer;
forming a nitride layer overlying the second semiconductor layer;
after forming the nitride layer, performing a rapid thermal anneal (RTA) in a non-oxidizing atmosphere at a temperature of 1000° C. or less for 50 seconds or less to diffuse the second semiconductor material into the first semiconductor layer;
performing a rapid thermal oxidation (RTO) in an oxidizing atmosphere to oxidize a remainder of the second semiconductor material into an oxide layer; and
removing the nitride layer and the oxide layer after performing the RTO.
13. The method of claim 12 wherein performing the RTA in the non-oxidizing atmosphere is for a shorter duration than performing the RTO in the oxidizing atmosphere.
14. The method of claim 12 wherein performing the RTA in the non-oxidizing atmosphere is at a higher temperature than performing the RTO in the oxidizing atmosphere.
15. The method of claim 12 wherein the second semiconductor material comprises germanium, and the first semiconductor material comprises silicon.