Selective emitter photovoltaic device
AssigneeInternational Business Machines Corporation
InventorsBahman Hekmatshoartabari, Ali Khakifirooz, Devendra K. Sadana, Ghavam G. Shahidi, Davood Shahrjerdi
Life of this patent
Estimating the term…
Abstract
A method for fabricating a photovoltaic device includes forming a patterned layer on a doped emitter portion of the photovoltaic device, the patterned layer including openings that expose areas of the doped emitter portion and growing an epitaxial layer over the patterned layer such that a crystalline phase grows in contact with the doped emitter portion and a non-crystalline phase grows in contact with the patterned layer. The non-crystalline phase is removed from the patterned layer. Conductive contacts are formed on the epitaxial layer in the openings to form a contact area for the photovoltaic device.
Claims20
A photovoltaic device, comprising:
- a contact area including:
- a doped emitter layer having a first conductivity on a substrate having a second conductivity;
- a patterned layer formed on the doped emitter layer, the patterned layer including openings that expose areas of the doped emitter layer;
- an epitaxial layer having a crystalline phase grown in contact with an upper surface of the doped emitter portion, the epitaxial layer having a same conductivity type as the doped emitter layer with a greater doping concentration than the doped emitter layer, the dopant concentration of the epitaxial layer ranging from 1×1018 cm−3 to 3×1020 cm−3;
- a diffusion region having a first conductivity extending from the epitaxial layer into the doped emitter layer, wherein a dopant concentration that provides the first conductivity in the diffusion region having a greater dopant concentration than other portions of the doped emitter layer, the diffusion region has a depth ranging from between 40% and 60% of the thickness of the epitaxial layer, as measured from an interface between the doped emitter layer and the epitaxial layer;
- and
- conductive contacts formed on the epitaxial layer in the openings.
A photovoltaic device, comprising:
- a first emitter formed on a monocrystalline substrate;
- a patterned layer formed on the first emitter, the patterned layer including openings that expose areas of the first emitter;
- an epitaxial layer formed in the openings of the patterned layer such that a crystalline phase grows in contact with the first emitter and forms a second emitter, the dopant concentration of the second emitter being greater than the first emitter, the dopant concentration of the second emitter ranging from 1×1018 cm−3 to 3×1020 cm−3;
- at least one passivation layer on the epitaxial layer having a composition selected from the group consisting of amorphous hydrogenated silicon, nanocrystalline hydrogenated silicon, microcrystalline hydrogenated silicon and a combination thereof, wherein the at least one passivation layer has a thickness ranging from 1 nm to 15 nm, and the at least one passivation layer is present only on the portion of the epitaxial layer that is present in the openings of the patterned layer;
- and
- metal fingers formed on the passivation layer in the openings to form a contact area.
A photovoltaic device, comprising:
- a first emitter formed on a monocrystalline substrate;
- a patterned layer formed on the first emitter, the patterned layer including openings that expose areas of the first emitter, the patterned layer including one or more of a passivation layer and an anti-reflection coating;
- highly doped diffusion regions formed in the first emitter and having a dopant concentration greater than other portions of the first emitter, the highly doped diffusion regions corresponding with locations of the openings in the patterned layer, wherein the highly doped diffusion regions have a depth ranging from between 40% and 60% of the thickness of the first emitter;
- an epitaxial layer formed in the openings of the patterned layer such that a crystalline phase is in contact with an upper surface of the first emitter and forms a second emitter, the dopant concentration of the second emitter ranging from 1×1018 cm-3 to 3×1020 cm-3;
- and
- metal fingers formed on the epitaxial layer in the openings to form a contact area.
Dependencies are inferred from the claim text.