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U.S. Department of Energy
Office of Scientific and Technical Information

Processes for producing low cost, high efficiency silicon solar cells

Patent ·
OSTI ID:672537

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. 28 figs.

Sponsoring Organization:
USDOE, Washington, DC (United States)
Assignee:
Georgia Tech Research Corp., Atlanta, GA (United States)
Patent Number(s):
US 5,766,964/A/
Application Number:
PAN: 8-579,074; CNN: Contract E21-H21; Contract E21-H31
OSTI ID:
672537
Country of Publication:
United States
Language:
English