Method of preventing autodoping
AssigneeMatrix Semiconductor, Inc.
InventorsScott B. Herner, James M. Cleeves, Johan Knall
Life of this patent
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Abstract
A method of making a silicon-based electronic device is provided. The method includes, for example, the steps of forming a doped silicon layer on a surface of a substrate material and forming an undoped silicon capping layer on the doped silicon layer. The thin “capping” layers of undoped silicon prevent outgassing of the dopants underneath the cap. In this manner, the next deposition of doped silicon is not subject to autodoping by the previous doped silicon deposition.
Claims23
A method of making a silicon-based electronic device comprising the steps of:
- forming a first doped silicon layer in a pressure vessel over a surface of a product wafer substrate material while introducing a precursor gas, the first doped layer comprising n-type or p-type silicon;
- without removing the substrate material from the pressure vessel, discontinuing introduction of the precursor gas and forming an undoped silicon capping layer on the first doped silicon layer, the undoped silicon capping layer having a thickness sufficient to reduce autodoping to approximately a back-ground level;
- and
- forming a next doped silicon layer on the undoped silicon capping layer, the next doped layer comprising p-type or n-type silicon, the type opposite the type of the first doped layer.
A method of making a silicon-based electronic device comprising the steps of:
- forming a first doped layer over a substrate by in-situ doping silicon with n-type or p-type dopant atoms;
- forming an undoped silicon capping layer on the first doped layer, the silicon capping, layer having a thickness sufficient to reduce autodoping to approximately a background level;
- and
- forming a second doped layer on the capping layer by in-situ doping silicon with p-type or n-type dopant atoms, the dopant type the opposite of the first doped layer,
- wherein the steps of forming the first doped layer and forming the silicon capping layer take place without removing the substrate from a chamber.
A continuous method of making a silicon-based electronic device comprising the steps of:
- introducing at least one substrate wafer into a chemical vapor deposition chamber;
- forming a first doped layer over the substrate wafer by introducing a first gas having silicon and a second gas having a p-type or n-type doping characteristic;
- forming a silicon capping layer on the first doped layer by discontinuing the introduction of the second gas while continuing the introduction of the first gas;
- and
- forming a second doped material on the capping layer by introducing a third gas having an n-type or p-type doping characteristic while continuing to introduce the first gas, the doping characteristic type of the third pas opposite the doping characteristic type of the second gas,
- wherein the step of forming a first doped layer and the step of forming a silicon capping layer take place without removing the substrate from the chamber, and
- wherein the silicon capping layer has a thickness sufficient to reduce autodoping to approximately a background level.
A method of reducing the effects of autodoping in a chemical vapor deposition furnace comprising the steps of:
- forming an undoped silicon capping layer between a first in-situ doped silicon layer and a second in-situ doped silicon layer, wherein the forming of the undoped silicon capping layer comprises forming an undoped silicon capping layer having a thickness sufficient to reduce the effects of autodoping to substantially a background level while maintaining the first and second doped silicon layers in operative communication with each other,
- wherein the first doped layer is formed with an n-type dopant or a p-type dopant, and
- the second doped layer is formed with a p-type dopant or an n-type dopant, the type opposite the type of the first doped layer.
Dependencies are inferred from the claim text.