TY - JOUR

T1 - Effective surface passivation of crystalline silicon using ultrathin Al2O3 films and Al2O3/SiN x stacks

AU - Schmidt, Jan

AU - Veith, Boris

AU - Brendel, Rolf

N1 - Funding Information: Funding was provided by the State of Lower Saxony and the German Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) under contract number 0325050 (“ALD”).

PY - 2009

Y1 - 2009

N2 - We measure surface recombination velocities (SRVs) below 10 cm/s on p-type crystalline silicon wafers passivated by atomic-layer-deposited (ALD) aluminium oxide (Al2O3) films of thickness ≥10 nm. For films thinner than 10 nm the SRV increases with decreasing Al2O3 thickness. For ultrathin Al2O3 layers of 3.6 nm we still attain a SRV < 22 cm/s on 1.5 Ω cm p-Si and an exceptionally low SRV of 1.8 cm/s on high-resistivity (200 Ω cm) p-Si. Ultrathin Al 2O3 films are particularly relevant for the implementation into solar cells, as the deposition rate of the ALD process is extremely low compared to the frequently used plasma-enhanced chemical vapour deposition of silicon nitride (SiNx). Our experiments on silicon wafers passivated with stacks composed of ultrathin Al2O3 and SiN x show that a substantially improved thermal stability during high-temperature firing at 830 °C is obtained for the Al2O 3/SiNx stacks compared to the single-layer Al 2O3 passivation. Al2O3/SiN x stacks are hence ideally suited for the implementation into industrial-type silicon solar cells where the metal contacts are made by screen-printing and high-temperature firing of metal pastes.

AB - We measure surface recombination velocities (SRVs) below 10 cm/s on p-type crystalline silicon wafers passivated by atomic-layer-deposited (ALD) aluminium oxide (Al2O3) films of thickness ≥10 nm. For films thinner than 10 nm the SRV increases with decreasing Al2O3 thickness. For ultrathin Al2O3 layers of 3.6 nm we still attain a SRV < 22 cm/s on 1.5 Ω cm p-Si and an exceptionally low SRV of 1.8 cm/s on high-resistivity (200 Ω cm) p-Si. Ultrathin Al 2O3 films are particularly relevant for the implementation into solar cells, as the deposition rate of the ALD process is extremely low compared to the frequently used plasma-enhanced chemical vapour deposition of silicon nitride (SiNx). Our experiments on silicon wafers passivated with stacks composed of ultrathin Al2O3 and SiN x show that a substantially improved thermal stability during high-temperature firing at 830 °C is obtained for the Al2O 3/SiNx stacks compared to the single-layer Al 2O3 passivation. Al2O3/SiN x stacks are hence ideally suited for the implementation into industrial-type silicon solar cells where the metal contacts are made by screen-printing and high-temperature firing of metal pastes.

UR - http://www.scopus.com/inward/record.url?scp=73949100676&partnerID=8YFLogxK

U2 - 10.1002/pssr.200903272

DO - 10.1002/pssr.200903272

M3 - Article

AN - SCOPUS:73949100676

VL - 3

SP - 287

EP - 289

JO - Physica Status Solidi - Rapid Research Letters

JF - Physica Status Solidi - Rapid Research Letters

SN - 1862-6254

IS - 9

ER -