Method of manufacturing semiconductor device

1. A method of forming a semiconductor device, the method comprising:

epitaxially growing a bulk source/drain region onto a substrate by simultaneously and continuously introducing a first precursor, a second precursor, and an etching precursor to the substrate for a time period of about 500 seconds, the first precursor being dichlorosilane, the second precursor being phosphine, the etching precursor being hydrochloric acid;

cleaning the bulk source/drain region by simultaneously and continuously introducing the etching precursor and a shaping precursor to the substrate for a time period of about 100 seconds, the shaping precursor being germane, wherein the cleaning the bulk source/drain region modifies a crystalline structure of a surface of the bulk source/drain region, wherein the cleaning the bulk source/drain region forms a shaping section with a first concentration of germanium; and

epitaxially growing a finishing region onto the bulk source/drain region by simultaneously and continuously introducing the first precursor, the second precursor, and the etching precursor to the substrate for a time period of about 100 seconds, the finishing region being grown after the cleaning the bulk source/drain region.

2. The method of claim 1 , wherein the cleaning the bulk source/drain region comprises introducing germanium into the bulk source/drain region.

3. The method of claim 1 , wherein the substrate comprises a first fin.

4. The method of claim 3 , wherein the substrate comprises a second fin adjacent to the first fin and separated by a distance of no greater than 100 nm.

5. A method of forming a semiconductor device, the method comprising:

growing a first layer of a first material onto a substrate in a first step, wherein the growing the first layer comprises simultaneously and continuously introducing a first precursor, a second precursor, and an etchant to the substrate until the first layer is a first thickness, the etchant having a first lateral etch rate of the first material;

growing a second layer of a second material onto the first layer in a second step after the first step, wherein the growing the second layer comprises simultaneously and continuously introducing the etchant and a shaping precursor to the substrate until the second layer is a second thickness, the second thickness being less than the first thickness, the shaping precursor having a second lateral etch rate of the first material; and

growing a third layer of the first material onto the second layer in a third step after the second step, wherein the growing the second layer of the first material comprises simultaneously and continuously introducing the first precursor, the second precursor, and the etchant to the substrate until the third layer is a third thickness, the third thickness being less than the first thickness.

6. The method of claim 5 , wherein the second material has a different lattice structure than the first material.

7. The method of claim 6 , wherein the first material is silicon phosphorous and the second material is germanium-doped silicon phosphorous.

8. The method of claim 7 , wherein the etchant is hydrochloric acid.

9. The method of claim 5 , wherein the first precursor is dichlorosilane and the second precursor is PH 3 .

10. The method of claim 5 , wherein the growing the first layer is performed with a first set of process conditions and the growing the second layer is performed with the first set of process conditions but a different time.

11. The method of claim 5 , wherein the second lateral etch rate is greater than the first lateral etch rate.