International Business Machines Corporation

E.i. Dupont De Nemours and Company

Piquant Research LLC

Innovalight, Inc.

Daniel Aneurin Inns

Devendra K Sadana

Katherine Lynn Saenger

Dmitry Poplavskyy

Stephen W Bedell

Keith E Fogel

Jeehwan Kim

Joel Pereira De Souza

Harold John Hovel

Giuseppe Scardera

Shannon Dugan

Karim Lotfi Bendimerad

Alexander Reznicek

Ghavam G Shahidi

Davood Shahrjerdi

Christian Lavoie

Zhen Zhang

Maxim Kelman

Jee Hwan Kim

Karim Lofti Bendimerad

A solar cell having n-type and p-type interdigitated back contacts (IBCs), which cover the entire back surface of the absorber layer. The spatial separation of the IBCs is in a direction perpendicular to the back surface, thus providing borderless contacts having a zero-footprint separation. As the contacts are on the back, photons incident on the cell's front surface can be absorbed without any shadowing.

Solar cell with interdigitated back contacts formed from high and low work-function-tuned silicides of the same metal

A method for manufacturing an interdigitated back contact solar cell, comprising steps of: (a) providing a doped silicon substrate; (b) doping the rear surface of the substrate homogeneously with boron in a blanket pattern, thereby forming a p+ region on the rear surface of the silicon substrate; (c) forming a silicon dioxide layer on the front and rear surface; (d) depositing a phosphorus-containing doping paste on the rear surface in a second pattern; (e) heating the silicon substrate to locally diffuse phosphorus into the rear surface of the silicon substrate, thereby forming an n+ region on the rear surface of the silicon substrate through the second pattern, wherein the p+ region and the n+ region on the rear surface collectively form an interdigitated pattern; and (f) removing the second silicon dioxide layer from the silicon substrate.

Method for manufacturing an interdigitated back contact solar cell

A method for manufacturing an interdigitated back contact solar cell. comprising the steps of: (a) providing a silicon substrate doped with a first dopant; (b) doping the rear surface of the silicon substrate with a second dopant in a first pattern; (c) forming a silicon dioxide layer on the rear surface; (d) depositing a silicon-containing paste comprising silicon-containing particles on the silicon dioxide layer in a second pattern; (e) exposing the substrate to a diffusion ambient, wherein the diffusion ambient comprises a third dopant and wherein the third dopant is a counter dopant to the second dopant; (f) heating the substrate in a drive-in ambient; and (g) removing the silicon dioxide layer and the doped silicate glass layer from the silicon substrate, wherein a region doped with the second dopant and a region doped with the third dopant collectively form an interdigitated pattern on the rear surface of the silicon substrate.

A method for manufacturing an interdigitated back contact solar cell, comprising steps of: (a) providing a doped silicon substrate; (b) forming a first silicon dioxide layer on the front surface and the rear surface; (c) depositing a boron-containing doping paste on the first silicon dioxide layer of the rear surface in a first pattern; (d) heating the silicon substrate; (e) removing the first silicon dioxide layer; (f) forming a second silicon dioxide layer on the front surface and the rear surface; (g) depositing a phosphorus-containing doping paste on the second dioxide layer of the rear surface in a second pattern; (h) heating the silicon substrate; and (i) removing the second silicon dioxide layer from the silicon substrate, wherein the first pattern and the second pattern collectively form an interdigitated pattern.

A method selectively diffuses dopants into a substrate wafer. The method comprises blanket depositing a doped liquid precursor including dopants on a surface of the substrate wafer to create a doped film on the surface of the substrate wafer, selectively forming a diffusion source in the doped film to selectively diffuse the dopants into the substrate wafer, and heating the doped film on the substrate wafer, wherein said heating the doped film diffuses the dopants from the doped film into the substrate wafer.

Diffusion sources from liquid precursors

A germanium-containing layer is deposited on a single crystalline bulk silicon substrate in an ambient including a level of oxygen partial pressure sufficient to incorporate 1%-50% of oxygen in atomic concentration. The thickness of the germanium-containing layer is preferably limited to maintain some degree of epitaxial alignment with the underlying silicon substrate. Optionally, a graded germanium-containing layer can be grown on, or replace, the germanium-containing layer. An at least partially crystalline silicon layer is subsequently deposited on the germanium-containing layer. A handle substrate is bonded to the at least partially crystalline silicon layer. The assembly of the bulk silicon substrate, the germanium-containing layer, the at least partially crystalline silicon layer, and the handle substrate is cleaved within the germanium-containing layer to provide a composite substrate including the handle substrate and the at least partially crystalline silicon layer. Any remaining germanium-containing layer on the composite substrate is removed.

Germanium-containing release layer for transfer of a silicon layer to a substrate

A solar cell, comprising: a doped silicon substrate, the silicon substrate comprising a front surface and a rear surface; a front phosphorous diffusion layer formed on the front surface; a front anti-reflective layer formed on the front phosphorous diffusion layer; a front metal electrode on the front surface in ohmic contact with the front phosphorous diffusion layer through the front anti-reflective layer; a rear passivation layer formed on the rear surface; a rear metal electrode in a pattern on the rear surface passing through the rear passivation layer; and a rear p+ diffusion area on the rear surface between the rear passivation layer and a boron-doped region of the silicon substrate, the rear p+ diffusion area surrounding the rear metal electrode.

Methods of forming a high efficiency solar cell with a localized back surface field

Methods for selectively diffusing dopants into a substrate wafer are provided. A liquid precursor is doped with dopants. The liquid precursor is selected from a group comprising monomers, polymers, and oligomers of silicon and hydrogen. The doped liquid precursor is deposited on a surface of the substrate wafer to create a doped film. The doped film is heated on the substrate wafer for diffusing the dopants from the doped film into the substrate wafer at different diffusion rates to create a heavily diffused region and a lightly diffused region in the substrate wafer. The method disclosed herein further comprises selective curing of the doped film on the surface of the substrate wafer. The selectively cured doped film acts as a diffusion source for selectively diffusing the dopants into the substrate wafer.

A photovoltaic device includes a composition modulated semiconductor structure including a p-doped first semiconductor material layer, a first intrinsic compositionally-graded semiconductor material layer, an intrinsic semiconductor material layer, a second intrinsic compositionally-graded semiconductor layer, and an n-doped first semiconductor material layer. The first and second intrinsic compositionally-graded semiconductor material layers include an alloy of a first semiconductor material having a greater band gap width and a second semiconductor material having a smaller band gap with, and the concentration of the second semiconductor material increases toward the intrinsic semiconductor material layer in the first and second compositionally-graded semiconductor material layers. The photovoltaic device provides an open circuit voltage comparable to that of the first semiconductor material, and a short circuit current comparable to that of the second semiconductor material, thereby increasing the efficiency of the photovoltaic device.

Compositionally-graded band gap heterojunction solar cell

The invention provides a high temperature (about 1150&#xb0; C. or greater) annealing process for converting thick polycrystalline Si layers on the order of 1 &#x3bc;m to 40 &#x3bc;m on a single crystal seed layer into thick single crystal Si layers having the orientation of the seed layer, thus allowing production of thick Si films having the quality of single crystal silicon at high rates and low cost of processing. Methods of integrating such high temperature processing into solar cell fabrication are described, with particular attention to process flows in which the seed layer is disposed on a porous silicon release layer. Another aspect pertains to the use of similar high temperature anneals for poly-Si grain growth and grain boundary passivation. A further aspect relates to structures in which these thick single crystal Si films and passivated poly-Si films are incorporated.

Thick epitaxial silicon by grain reorientation annealing and applications thereof

A method for improving the minority lifetime of silicon containing wafer having metallic contaminants therein is described incorporating annealing at 1200&#xb0; C. or greater and providing a gaseous ambient of oxygen, an inert gas and a chlorine containing gas such as HCl.

Crystalline silicon substrates with improved minority carrier lifetime including a method of annealing and removing SiOx precipitates and getterning sites

Growing community of inventors

Palo Alto, CA, United States of America

Daniel Aneurin Inns