High efficiency low cost thin film silicon solar cell design and method for making

Patent · Fri Jan 01 00:00:00 EST 1999

OSTI ID:872261

Sopori, Bhushan L ^[1]

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1. Denver, CO

A semiconductor device having a substrate, a conductive intermediate layer deposited onto said substrate, wherein the intermediate layer serves as a back electrode, an optical reflector, and an interface for impurity gettering, and a semiconductor layer deposited onto said intermediate layer, wherein the semiconductor layer has a grain size at least as large as the layer thickness, and preferably about ten times the layer thickness. The device is formed by depositing a metal layer on a substrate, depositing a semiconductive material on the metal-coated substrate to produce a composite structure, and then optically processing the composite structure by illuminating it with infrared electromagnetic radiation according to a unique time-energy profile that first produces pits in the backside surface of the semiconductor material, then produces a thin, highly reflective, low resistivity alloy layer over the entire area of the interface between the semiconductor material and the metal layer, and finally produces a grain-enhanced semiconductor layer. The time-energy profile includes increasing the energy to a first energy level to initiate pit formation and create the desired pit size and density, then ramping up to a second energy level in which the entire device is heated to produce an interfacial melt, and finally reducing the energy to a third energy level and holding for a period of time to allow enhancement in the grain size of the semiconductor layer.

• Research Organization: Midwest Research Institute, Kansas City, MO (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-83CH10093
• Assignee: Midwest Research Institute (Kansas City, MO)
• Patent Number(s): US 5897331
• OSTI ID: 872261
• Country of Publication: United States
• Language: English

Related Subjects

efficiency
cost
film
silicon
solar
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design
method
semiconductor
device
substrate
conductive
intermediate
layer
deposited
serves
electrode
optical
reflector
interface
impurity
gettering
grain
size
thickness
preferably
times
formed
depositing
metal
semiconductive
material
metal-coated
produce
composite
structure
optically
processing
illuminating
infrared
electromagnetic
radiation
according
unique
time-energy
profile
produces
pits
backside
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highly
reflective
resistivity
alloy
entire
finally
grain-enhanced
increasing
energy
level
initiate
pit
formation
create
desired
density
ramping
heated
interfacial
melt
reducing
third
holding
period
time
allow
enhancement
semiconductive material
time-energy profile
impurity gettering
layer serves
highly reflective
energy level
composite structure
metal layer
electromagnetic radiation
conductive material
solar cell
semiconductor material
semiconductor layer
silicon solar
grain size
semiconductor device
intermediate layer
layer deposited
alloy layer
coated substrate
cell design
layer thickness
resistivity alloy
backside surface
produces pits
pit size
optically processing
film silicon
entire device
desired pit
unique time
conductive intermediate
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