Fabrication of quantum confinement semiconductor light-emitting devices
AssigneeXerox Corporation
InventorsDavid K. Biegelsen, Nicholas K. Sheridon, Noble M. Johnson
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Abstract
The present invention consists of an electroluminescent structure and method of fabrication of that structure in materials which have an indirect bandgap in their bulk form. The processing steps can all be standard VLSI methods. Quantum columns, quantum wires or quantum dots may be formed, for example in an array, by masking, reactive ion etching and oxidation. When the semiconductor core is sufficiently thin, quantum mechanical confinement effects raise the energy and the radiative recombination efficiency of injected carriers. Tuning the core diameters allows selection of individual or multiple wavelength emission bands.
Claims24
A method for fabricating a quantum nanowire, comprising the steps of:
- providing a substrate of an indirect bandgap semiconducting material;
- forming a p-n junction on a surface of the substrate, the p-n junction having a first region of a first conductivity type adjacent and below a second region of a second conductivity type wherein the first region is formed in the substrate;
- etching the first region and the second region to form a column of indirect bandgap semiconducting material;
- oxidizing the column while retaining unoxidized a vertical core of the column, said oxidizing step enabling quantum carrier confinement in two dimensions;
- and
- connecting the first region and the second region with electrical contacts so that the vertical core may be electrically biased.
A method according to claim 11, wherein said connecting step induces carrier recombination so that the column emits light.
A method for fabricating an array of quantum nanowires, comprising the steps of:
- providing a substrate of an indirect bandgap semiconducting material;
- forming on a surface of the substrate a first region of a first conductivity type, said forming step including the step of forming a second region of a second conductivity type adjacent and above the first region;
- etching the first region and the second region to form an array of columns of indirect bandgap semiconducting material;
- oxidizing the array of columns while retaining unoxidized a vertical core of each of the columns, said oxidizing step forming an array of vertical cores that enable quantum carrier confinement in two dimensions;
- and
- depositing a generally transparent metal layer over the array of vertical cores, the generally transparent metal layer providing electrical communication with each of the vertical cores.
A method for forming an array of quantum nanowires on a substrate of crystalline silicon material, comprising the steps of:
- forming a buffed oxide layer in the crystalline silicon substrate below a crystalline silicon layer;
- doping the crystalline silicon layer to form a first region of the crystalline silicon substrate with p-type impurities and a second region of the crystalline silicon substrate adjoining the first region with n-type impurities, the first region and the second region being formed above the buffed oxide layer and in an unoxidized portion of the crystalline silicon substrate;
- growing a surface oxide layer in both the first region and the second region of the crystalline silicon substrate, said growing step retaining a layer of the first region and the second region between the buffed oxide layer and the surface oxide layer;
- depositing silicon nitride stripe regions on the surface oxide layer, the silicon nitride stripe regions overlaying a portion of the first region and the second region;
- oxidizing the first region and the second region, said oxidizing step using the silicon nitride stripe regions as masks to form unoxidized core regions of the first region and the second region, each unoxidized core region including a p-n junction that enables quantum carrier confinement in multiple dimensions;
- and
- forming electrical contacts to the first region and the second region.
Dependencies are inferred from the claim text.