Abstract
We observe a degradation of the minority-carrier lifetime in silicon substrates after a temperature cycle in a molecular beam epitaxy (MBE) chamber that is representative of the growth of III-V materials. This decrease in the lifetime is from milliseconds to microseconds, and in some cases into the sub-microsecond range. The degradation appears to be caused by thermally activated diffusion of metals from the back side of the substrate, occurring at temperatures above 500 °C. This impacts the ability to achieve high-performance monolithic III-V/Si multi-junction solar cells, since the epitaxial growth usually requires high-temperature steps (over 700 °C) for surface de-oxidation or surface reconstruction and temperatures of 400-600 °C during the epitaxial growth. We show that, through phosphorous diffusion gettering, the lifetimes of degraded wafers can be recovered to the millisecond range. Further, we demonstrate that a silicon nitride coating functions both as a diffusion barrier and as an interfacial gettering or hydrogenation agent, enabling high minority-carrier lifetimes directly out of the MBE chamber. This approach allows for the silicon minority-carrier lifetime to be maintained in the millisecond range without the need for post-growth recovery, providing a path to achieve high-efficiency III-V/Si solar cells.
| Original language | English (US) |
|---|---|
| Article number | 8625581 |
| Pages (from-to) | 431-436 |
| Number of pages | 6 |
| Journal | IEEE Journal of Photovoltaics |
| Volume | 9 |
| Issue number | 2 |
| DOIs | |
| State | Published - Mar 1 2019 |
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Keywords
- diffusion barrier
- III-V/Si integration
- minoritycarrier lifetime
- molecular beam epitaxy (MBE)
- SiN
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
Cite this
Silicon Nitride Barrier Layers Mitigate Minority-Carrier Lifetime Degradation in Silicon Wafers during Simulated MBE Growth of III-V Layers. / Zhang, Chaomin; Ding, Laura; Boccard, Mathieu; Narland, Tine U.; Faleev, Nikolai; Bowden, Stuart; Bertoni, Mariana; Honsberg, Christiana; Holman, Zachary.
In: IEEE Journal of Photovoltaics, Vol. 9, No. 2, 8625581, 01.03.2019, p. 431-436.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Silicon Nitride Barrier Layers Mitigate Minority-Carrier Lifetime Degradation in Silicon Wafers during Simulated MBE Growth of III-V Layers
AU - Zhang, Chaomin
AU - Ding, Laura
AU - Boccard, Mathieu
AU - Narland, Tine U.
AU - Faleev, Nikolai
AU - Bowden, Stuart
AU - Bertoni, Mariana
AU - Honsberg, Christiana
AU - Holman, Zachary
PY - 2019/3/1
Y1 - 2019/3/1
N2 - We observe a degradation of the minority-carrier lifetime in silicon substrates after a temperature cycle in a molecular beam epitaxy (MBE) chamber that is representative of the growth of III-V materials. This decrease in the lifetime is from milliseconds to microseconds, and in some cases into the sub-microsecond range. The degradation appears to be caused by thermally activated diffusion of metals from the back side of the substrate, occurring at temperatures above 500 °C. This impacts the ability to achieve high-performance monolithic III-V/Si multi-junction solar cells, since the epitaxial growth usually requires high-temperature steps (over 700 °C) for surface de-oxidation or surface reconstruction and temperatures of 400-600 °C during the epitaxial growth. We show that, through phosphorous diffusion gettering, the lifetimes of degraded wafers can be recovered to the millisecond range. Further, we demonstrate that a silicon nitride coating functions both as a diffusion barrier and as an interfacial gettering or hydrogenation agent, enabling high minority-carrier lifetimes directly out of the MBE chamber. This approach allows for the silicon minority-carrier lifetime to be maintained in the millisecond range without the need for post-growth recovery, providing a path to achieve high-efficiency III-V/Si solar cells.
AB - We observe a degradation of the minority-carrier lifetime in silicon substrates after a temperature cycle in a molecular beam epitaxy (MBE) chamber that is representative of the growth of III-V materials. This decrease in the lifetime is from milliseconds to microseconds, and in some cases into the sub-microsecond range. The degradation appears to be caused by thermally activated diffusion of metals from the back side of the substrate, occurring at temperatures above 500 °C. This impacts the ability to achieve high-performance monolithic III-V/Si multi-junction solar cells, since the epitaxial growth usually requires high-temperature steps (over 700 °C) for surface de-oxidation or surface reconstruction and temperatures of 400-600 °C during the epitaxial growth. We show that, through phosphorous diffusion gettering, the lifetimes of degraded wafers can be recovered to the millisecond range. Further, we demonstrate that a silicon nitride coating functions both as a diffusion barrier and as an interfacial gettering or hydrogenation agent, enabling high minority-carrier lifetimes directly out of the MBE chamber. This approach allows for the silicon minority-carrier lifetime to be maintained in the millisecond range without the need for post-growth recovery, providing a path to achieve high-efficiency III-V/Si solar cells.
KW - diffusion barrier
KW - III-V/Si integration
KW - minoritycarrier lifetime
KW - molecular beam epitaxy (MBE)
KW - SiN
UR - http://www.scopus.com/inward/record.url?scp=85062225961&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85062225961&partnerID=8YFLogxK
U2 - 10.1109/JPHOTOV.2019.2892522
DO - 10.1109/JPHOTOV.2019.2892522
M3 - Article
AN - SCOPUS:85062225961
VL - 9
SP - 431
EP - 436
JO - IEEE Journal of Photovoltaics
JF - IEEE Journal of Photovoltaics
SN - 2156-3381
IS - 2
M1 - 8625581
ER -