Oxygen enhanced metastable silicon germanium film layer

Abstract

A method for pseudomorphic growth and integration of a strain-compensated metastable and/or unstable compound base having incorporated oxygen and an electronic device incorporating the base is described. The strain-compensated base is doped by substitutional and/or interstitial placement of a strain-compensating atomic species. The electronic device may be, for example, a SiGe NPN HBT.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary film stack 100 used in forming a strain-compensated metastable base layer of a heterojunction bipolar transistor (HBT).

FIG. 2 is an exemplary graph for determining critical thickness of a strain-compensated metastable SiGe base region as a function of germanium content.

FIGS. 3 and 4 are x-ray diffraction rocking curves.

FIGS. 5-7 are various germanium concentration profiles which may be used in an HBT device.

Claims

1. A method for fabricating a compound semiconductor film, the method comprising: providing a substrate, the substrate having a first surface;forming the compound semiconductor film over the first surface of the substrate, the compound semiconductor film having a substantially crystalline lattice structure, the compound semiconductor film further having a high concentration of a first semiconducting material of the compound semiconductor such that the compound semiconductor is in a metastable state;incorporating oxygen into the crystalline lattice structure; anddoping the compound semiconductor film with a strain-compensating atomic species.

2. The method of claim 1, further comprising selecting a concentration of the strain-compensating species to control a defect density and enhance bandgap or lattice characteristics.

3. The method of claim 1 wherein the compound semiconductor is selected to be silicon germanium.

4. The method of claim 3 wherein the first semiconducting material of the selected compound semiconductor is comprised substantially of germanium.

5. The method of claim 1 wherein the strain-compensating species is selected to be carbon.

6. The method of claim 1 wherein the strain-compensating species is selected to reduce a lattice strain of the compound semiconductor.

7. The method of claim 1 wherein the strain-compensating species is selected to increase a lattice strain of the compound semiconductor.

8. The method of claim 1 wherein the step of doping the compound semiconductor film with the strain-compensating atomic species is performed in-situ.

9. The method of claim 1 further comprising profiling the first semiconducting material to have a trapezoidal shape.

10. The method of claim 1 further comprising profiling the first semiconducting material to have a triangular shape.

11. The method of claim 1 further comprising profiling the first semiconducting material to have a semicircular shape.

12. The method of claim 1 wherein the step of formation of the compound semiconductor occurs at a temperature in a range of 500° C. to 900° C.

13. The method of claim 1 wherein the step of formation of the compound semiconductor occurs at a temperature of less than 600° C.

14. The method of claim 1 further comprising forming the compound semiconductor film to a thickness greater than a critical thickness, hc.

15. An electronic device comprising: a substrate;a compound semiconductor film disposed over a first surface of the substrate, the compound semiconductor film having a substantially crystalline lattice structure with incorporated oxygen, the compound semiconductor film further having a high concentration of a first semiconducting material of the compound semiconductor such that the compound semiconductor film is in a metastable state; anda strain-compensating atomic species doped substitutionally into the compound semiconductor.

16. The electronic device of claim 15 wherein the compound semiconductor is comprised substantially of silicon germanium.

17. The electronic device of claim 16 wherein the first semiconducting material of the compound semiconductor is comprised substantially of germanium.

18. The electronic device of claim 15 wherein the strain-compensating species is carbon.

19. A method for fabricating a heterojunction bipolar transistor, the method comprising: providing a substrate, the substrate having a first surface;forming a silicon-germanium film over the first surface of the substrate, the silicon germanium film being formed to be in a metastable state;incorporating oxygen into a substantially crystalline lattice structure of the silicon-germanium film; anddoping the silicon-germanium semiconductor film with a strain-compensating atomic species, the strain-compensating atomic species selected to be carbon.

20. The method of claim 19 further comprising tailoring the first semiconducting material to have a trapezoidal concentration profile shape.

21. The method of claim 19 further comprising tailoring the first semiconducting material to have a triangular concentration profile shape.

22. The method of claim 19 further comprising tailoring the first semiconducting material to have a semicircular concentration profile shape.

23. The method of claim 19 further comprising forming the compound semiconductor film to a thickness greater than a critical thickness, hc.

24. A method for fabricating a compound semiconductor film, the method comprising: providing a substrate, the substrate having a first surface;forming the compound semiconductor film over the first surface of the substrate, the compound semiconductor film having a substantially crystalline lattice structure, the compound semiconductor film further having a high concentration of a first semiconducting material of the compound semiconductor such that the compound semiconductor is in an unstable state;incorporating oxygen into the crystalline lattice structure; anddoping the compound semiconductor film with a strain-compensating atomic species.

25. The method of claim 24 wherein the compound semiconductor is selected to be silicon germanium.

26. The method of claim 25 wherein the first semiconducting material of the selected compound semiconductor is comprised substantially of germanium.

27. The method of claim 24 wherein the strain-compensating species is selected to be carbon.

28. The method of claim 24 wherein the strain-compensating species is selected to reduce a lattice strain of the compound semiconductor.

29. The method of claim 24 wherein the strain-compensating species is selected to increase a lattice strain of the compound semiconductor.