The low-pressure chemical vapor deposition (LPCVD) of polycrystalline silicon was investigted. The physical system was described, as was the controlling process parameters and requirements for producing films for use as an integral portion of the solar cell contact system

Crotty, G. C.

Gallagher, B. D.

English

NASA Technical Reports Server

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LOW-PRESSURE, CHEM::CAL VAPOR DEPOSITION
POI.Y,'I.-.:i iCON
,_ JET PROPUL,£!r.,,.',' LABORATORY
B. D. Galle:, ,':, :-:'_dG. C. Crotty
l
_1 Polysilicon i_ .,-., _ !3r Contact Passivation to:
• Levee: surface recombination velocity
• Inm_ea._eVoc
- • Inc,ease cell efficiency
Reactor for LPCVD Polysilicon
PRESSURE
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483
1987006957-475
https://ntrs.nasa.gov/search.jsp?R=19870006993 2020-03-20T12:13:14+00:00Z
1
-; PROCESSING
Algorithm for the LPCVD Polysilicon Frocess
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484
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1987006957-476
PROCESSING
Flow Diagram for the LPCVD Polysilicon Process
r
,.._.._. MASKCONTACTAREA FRONTANDBACKMETAL
• i:' .ox] P.T,_EI ,• ,i .15-2511-cm
PH3 DIFFUSIOI_
N',-'--- "I--2 pm ETCHPOLYSILICONANDREMOVEPR
I I I I/, *. p -- -- -- ,..4__N+ ARCOAT
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ox,,._o,__ T_ ,""°v'.°v°°'..,.[....,,..:_......I• ,, I I
P lF ETCHCONTACTWINDOWS
r--I
' ] ANNEALANDOXIDIZE
. t L ..ox,.CVDDEPOSITIONOFPOLYSILICON, m
I== == == POLYSILICON
• [ 1I,
Sheet Resistance
TIME AS DEPOSITED POST ANNEAL
•_ [PH3]/[SiH4] (min) (ohms/square) (ohms/square)
2.5 x 10 -2 ,.,0 2320 178
120 1616 138
180 863 70
i
1987006957-477
{ PROCESSING l
al
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Secondary Ion Mass Spectroscopy Plot (25-4-3)
_._ J_'_ 61MS LFIB 24 Flpr 1986 13:54:22 _,
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Secondary Ion Mass Spectroscopy Plot (25-3-3)
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Secondary Ion Mass Spectrnscopy Plot (25-2-3BD6) ,
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Preliminary Electrical Results
(In-Situ Polysi;icon Doped with [PH3]/[SiH4] Ratio of 2.5 x 10-2)
Voc Isc FF _ t Ps :,,
/._-i- / -LI_,._ /zjr,_- 8/3 /_._, /,J-/,J" "7o
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Conclusions
._ • LPCVD System Operational
'" • Preliminary Electrical Results Encouraging
487
1987006957-479
i .
i
Module and Reliability Technology
MODULE TECHNOLOGY
, Melvin I. Smokier, Chai,man
R. Mueller, of JPL, described the measurement system requirements to obt_in
,_ accurate electrical performance measurements of mnorphous silicon cells _nd
_ modules, and reviewed progress in modifying the JPL system toward that
objective.
R. Ross, Jr., of JPL, discussed the JPL program of developing qualification
tests necessary for amorphous silicon modules, including eppropriate
accelerated environmental tests that reveal degradation due to illumination.
Data were given showing the results of temperature-controlled field tests and
the results of accelerated tests in an environmental chamber.
o
J. Lathrop, of Clemson University, reported progress and initial data on
accelerated stress tests on small amorphous silicon test samples from several
manufacturers. The test samples included both single and tandem junction
devices.
D. Otth, of JPL, presented the results of a current set of accelerated
long-term endurance tests on crystalline silicon modules of various
constructions. Cell materials include single crystal, semicrystal, EFG ribbon,
and dendritic web ribbon. The latest data set is for the equivalent of 20-year
life and showed satisfactory performance.
P. Willis, of Springborn Laboratory, reviewed work on identifying and
developing low-cost module encapsulation materials. Test results were
displayed for a variety of materials. The improved prospects for modeling
encapsulation systems for life prediction were reported.
M. Smokler, of JPL, presented the results of a program of qualification
testi:g of commercial crystalline silicon modules from nine manufacturers in
five countries. The outcome demonstrated the effective role of the Block V J,
Qualification Tests in the development of reliable modules. I
M. Spitzer, of Spire Corp., reported success in meeting the long-sought
goal cf manufacturing a crystalline silicon module with efficiency of 15% or
better. Encapsulate_ cell efficienci_s as high as 17.6% were obtained.
B. Jackson, of JPL, reviewed the role and some results of the project
analysis and integration function in the FSA Project. Activities included
/ supporting the decision-making process, preparation of plans for Project
direction, setting goals for Project activities, measuring progress within the
Project, and the development and maintenance of analytical models.
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1987006957-480


Low-pressure, chemical vapor deposition polysilicon

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