TY - JOUR

T1 - Carrier Lifetime Degradation and Regeneration in Gallium- and Boron-Doped Monocrystalline Silicon Materials

AU - Winter, Michael

AU - Walter, Dominic

AU - Schmidt, Jan

N1 - Funding Information: Manuscript received January 26, 2021; revised March 12, 2021; accepted March 30, 2021. Date of publication April 20, 2021; date of current version June 21, 2021. This work was supported in part by the German State of Lower Saxony and in part by the German Federal Ministry for Economic Affairs and Energy within the research project LIMES (contract 0324204D) (Corresponding author: Michael Winter.) Michael Winter and Jan Schmidt are with the Institute for Solar Energy Research Hamelin/Emmerthal (ISFH), 31860 Emmerthal, Germany, and also with the Institute of Solid-State Physics, Leibniz University Hannover, 30167 Hannover, Germany (e-mail: m.winter@isfh.de; j.schmidt@isfh.de).

PY - 2021/4/20

Y1 - 2021/4/20

N2 - In this article, carrier lifetime degradation phenomena on fired gallium-doped Czochralski-grown silicon (Cz-Si:Ga) and boron-doped float-zone silicon (FZ-Si:B) are observed. We examine lifetime degradation and regeneration as a function of illumination intensity and temperature and observe qualitatively similar degradation effects in both material classes, which are triggered by a fast-firing high-temperature step. Charge carrier injection, e.g., through illumination, is required to activate the defects responsible for degradation. The extent of degradation increases with increasing temperature, which is untypical for degradation effects reported before. Despite different degradation time constants are measured for Cz-Si:Ga and FZ-Si:B, the activation energies are for both materials in the narrow range $({0.58 \pm 0.04}){\boldsymbol{\ }}{{\bf eV}}$. The extracted activation energy is quite different compared with other degradation effects in silicon, suggesting a novel defect formation mechanism. Since the lifetime degradation is triggered by the fast-firing of the silicon wafers during the presence of a hydrogen-rich dielectric at the surface, the involvement of hydrogen in the defect reaction is very likely. During prolonged illumination at elevated temperature (135 °C), we observe a permanent regeneration of the lifetime, whereas at temperatures close to room temperature (36 °C), the defect deactivation is only temporary.

AB - In this article, carrier lifetime degradation phenomena on fired gallium-doped Czochralski-grown silicon (Cz-Si:Ga) and boron-doped float-zone silicon (FZ-Si:B) are observed. We examine lifetime degradation and regeneration as a function of illumination intensity and temperature and observe qualitatively similar degradation effects in both material classes, which are triggered by a fast-firing high-temperature step. Charge carrier injection, e.g., through illumination, is required to activate the defects responsible for degradation. The extent of degradation increases with increasing temperature, which is untypical for degradation effects reported before. Despite different degradation time constants are measured for Cz-Si:Ga and FZ-Si:B, the activation energies are for both materials in the narrow range $({0.58 \pm 0.04}){\boldsymbol{\ }}{{\bf eV}}$. The extracted activation energy is quite different compared with other degradation effects in silicon, suggesting a novel defect formation mechanism. Since the lifetime degradation is triggered by the fast-firing of the silicon wafers during the presence of a hydrogen-rich dielectric at the surface, the involvement of hydrogen in the defect reaction is very likely. During prolonged illumination at elevated temperature (135 °C), we observe a permanent regeneration of the lifetime, whereas at temperatures close to room temperature (36 °C), the defect deactivation is only temporary.

KW - Carrier lifetime

KW - Light-Induced Degradation (LID)

KW - degradation

KW - gallium

KW - regeneration

KW - silicon (Si)

UR - http://www.scopus.com/inward/record.url?scp=85104661546&partnerID=8YFLogxK

U2 - 10.1109/JPHOTOV.2021.3070474

DO - 10.1109/JPHOTOV.2021.3070474

M3 - Article

VL - 11

SP - 866

EP - 872

JO - IEEE journal of photovoltaics

JF - IEEE journal of photovoltaics

SN - 2156-3381

IS - 4

M1 - 9408946

ER -