Methods of forming doped regions in semiconductor substrates
Some embodiments include methods of forming one or more doped regions in a semiconductor substrate. Plasma doping may be used to form a first dopant to a first depth within the substrate. The first dopant may then be impacted with a second dopant to knock the first dopant to a second depth within the substrate. In some embodiments the first dopant is p-type (such as boron) and the second dopant is neutral type (such as germanium). In some embodiments the second dopant is heavier than the first dopant.
1. A method of forming a doped region in a semiconductor substrate comprising:
forming a boron-containing deposit across an upper surface of the substrate while implanting boron within the substrate;
impacting the boron-containing deposit with germanium to knock boron out of the deposit and into the substrate; and
cleaning the substrate; the cleaning removing the deposit and all of the germanium to leave a doped region within the substrate; the doped region comprising the boron and none of the germanium.
2. The method of claim 1 wherein the forming of the boron-containing deposit and the implanting of the boron comprises plasma doping with B 2 H 6 .
3. A method of forming a doped region in a semiconductor substrate comprising:
forming a boron-containing deposit across an upper surface of the substrate while implanting boron within the substrate;
ion bombarding a material into the substrate to knock boron out of the deposit and into the substrate; the ion bombarding being conducted under conditions which keep all of the material in the deposit; and
cleaning the substrate; the cleaning removing the deposit and all of the material to leave a doped region within the substrate; the doped region comprising boron and none of the material.
4. The method of claim 3 wherein the material comprises a primary element heavier than boron.
5. The method of claim 4 wherein the primary element is neutral-type.
6. The method of claim 4 wherein the primary element is germanium.
7. The method of claim 3 wherein the forming of the boron-containing deposit and the implanting of the boron comprises plasma doping with B 2 H 6 .
8. A method of forming a boron-doped region, comprising:
plasma doping with B 2 H 6 to provide boron dopant within a silicon-containing material; wherein the plasma doping forms a deposit across an upper surface of the silicon-containing material;
ion bombarding germanium, in the absence of a plasma, to knock boron dopant out of the deposit and into the silicon-containing material;
using the deposit as a screen to protect underlying silicon-containing material from any penetration by the germanium; the ion bombarding being conducted under conditions which keep all of the germanium in the deposit; and
removing the deposit and the germanium to leave a boron-doped region within the silicon-containing material.