Processes for producing low cost, high efficiency silicon solar cells

Patent · Tue Jun 16 00:00:00 EDT 1998

OSTI ID:871627

Rohatgi, Ajeet ^[1]; Doshi, Parag ^[2]; Tate, John Keith ^[3]; Mejia, Jose ^[4]; Chen, Zhizhang ^[5]

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1. Marietta, GA
2. Altanta, GA
3. Lawrenceville, GA
4. Atlanta, GA
5. Duluth, GA

Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO.sub.x. In a fourth RTP process, the process of applying front and back contacts is broken up into two separate respective steps, which enhances the efficiency of the cells, at a slight time expense. In a fifth RTP process, a second RTP step is utilized to fire and adhere the screen printed or evaporated contacts to the structure.

• Research Organization: Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
• DOE Contract Number: AC04-94AL85000
• Assignee: Georgia Tech Research Corporation (Atlanta, GA)
• Patent Number(s): US 5766964
• Application Number: 08/579074
• OSTI ID: 871627
• Country of Publication: United States
• Language: English

Related Subjects

processes
producing
cost
efficiency
silicon
solar
cells
utilize
rapid
thermal
processing
rtp
provided
inexpensively
preserve
minority
carrier
bulk
lifetime
tau
permit
selective
adjustment
depth
diffused
regions
including
emitter
surface
field
bsf
substrate
process
step
utilized
simultaneously
diffuse
phosphorus
aluminum
front
surfaces
respectively
moreover
situ
controlled
cooling
procedure
preserves
permits
simultaneous
diffusion
annealing
contacts
accomplished
third
accomplishes
double-layer
antireflection
passivation
coating
sio
fourth
applying
broken
separate
respective
steps
enhances
slight
time
expense
fifth
fire
adhere
screen
printed
evaporated
structure
solar cell
solar cells
silicon substrate
silicon solar
minority carrier
rtp process
rapid thermal
thermal processing
permits selective
passivation coating
cooling procedure
efficiency silicon
carrier bulk
rtp processes
respective steps
controlled cooling
utilize rapid
surface field
inexpensively producing
preserve minority
processes preserve
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