Increasing stabilized performance of amorphous silicon based devices produced by highly hydrogen diluted lower temperature plasma deposition
AssigneeAmoco/Enron Solar
InventorsYaun-Min Li, Murray S. Bennett, Liyou Yang
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Abstract
High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.
Claims7
A process comprising the steps of:
- fabricating semiconductor devices comprising a layer of amorphous silicon supported on a substrate, by plasma enhanced chemical vapor deposition of said amorphous silicon layer under the following conditions:
- a substrate temperature ranging from 80.degree. C. to 220.degree. C.;
- a pressure ranging from 2 to 50 Torr;
- a plasma discharge power density ranging from 20 to 150 mW/cm.sup.2 ;
- a feedstock gas highly diluted with a diluent gas selected from the group consisting of hydrogen, deuterium, and combinations thereof;
- said feedstock gas comprising at least one member of the group consisting of:
- silane, disilane, tetramethyl silane, SiF.sub.4, SiHF.sub.3, SiH.sub.2 Cl.sub.4, and other gases having the general formula Si.sub.N H.sub.2N+2-M Y.sub.M wherein;
- Si=silicon
- H=hydrogen or deuterium
- Y=a halogen
- N=positive integer .gtoreq.1
- M=positive integer;
- and 2N+2-M.gtoreq.0;
- and
- the dilution ratio of said diluent gas to said feedstock gas ranging from about 20:1 to about 400:1.
A process comprising the steps of:
- fabricating semiconductor devices comprising a layer of amorphous silicon supported on, a substrate, by plasma enhanced chemical vapor deposition of said amorphous silicon layer under the following conditions:
- a substrate temperature ranging from 20.degree. C. to 300.degree. C.;
- a plasma discharge current density ranging from 0.01 to 5 A/cm.sup.2 ;
- a feedstock gas highly diluted with a diluent gas selected from the group consisting of hydrogen, deuterium, and combinations thereof;
- said feedstock gas comprising at least one member of the group consisting of:
- silane, disilane, tetramethyl silane, SiF.sub.4, SiHF.sub.3, SiH.sub.2 Cl.sub.4, and other gases having the general formula Si.sub.N H.sub.2N+2-M Y.sub.M wherein;
- Si=silicon
- H=hydrogen or deuterium
- Y=a halogen
- N=positive integer .gtoreq.1
- M=positive integer;
- and 2N+2-M.gtoreq.0
- the dilution ratio of said diluent gas to said feedstock gas ranging from about 5:1 to about 200:1;
- and
- a pressure greater than 1.0 Torr to about 10 Torr.
Dependencies are inferred from the claim text.