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Title: Processes for producing low cost, high efficiency silicon solar cells

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. Silicon solar cell efficiencies of 16.9% have been achieved. 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.
Inventors:
 [1];  [2];  [3]
  1. (Marietta, GA)
  2. (Duluth, GA)
  3. (Atlanta, GA)
Issue Date:
OSTI Identifier:
870383
Assignee:
Georgia Tech Research Corporation (Atlanta, GA) OSTI
Patent Number(s):
US 5510271
Contract Number:
E21-H21; E21-H31
Country of Publication:
United States
Language:
English
Subject:
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; cell; efficiencies; 16; achieved; 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; 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; controlled cooling; utilize rapid; surface field; inexpensively producing; preserve minority; processes preserve; /438/136/