Silicon surface passivation by atomic layer deposited Al2O3

Thin Al2O3 films with a thickness of 7–30 nm synthesized by plasma-assisted atomic layer deposition (ALD) were used for surface passivation of crystalline silicon (c-Si) of different doping concentrations. The level of surface passivation in this study was determined by techniques based on photoconductance, photoluminescence, and infrared emission. Effective surface recombination velocities of 2 and 6 cm/s were obtained on 1.9 Ω cm n-type and 2.0 Ω cm p-type c-Si, respectively. An effective surface recombination velocity below 1 cm/s was unambiguously obtained for nearly intrinsic c-Si passivated by Al2O3. A high density of negative fixed charges was detected in the Al2O3 films and its impact on the level of surface passivation was demonstrated experimentally. The negative fixed charge density results in a flat injection level dependence of the effective lifetime on p-type c-Si and explains the excellent passivation of highly B-doped c-Si by Al2O3. Furthermore, a brief comparison is presented between the ...

[1]  C. Hwang,et al.  Comparison of Properties of an Al2O3 Thin Layers Grown with Remote O2 Plasma, H2O , or O3 as Oxidants in an ALD Process for HfO2 Gate Dielectrics , 2005 .

[2]  Rolf Brendel,et al.  20.1%‐efficient crystalline silicon solar cell with amorphous silicon rear‐surface passivation , 2005 .

[3]  A. Aberle,et al.  Optimization and characterization of remote plasma-enhanced chemical vapor deposition silicon nitride for the passivation of p-type crystalline silicon surfaces , 1998 .

[4]  R. Alcubilla,et al.  Effect of amorphous silicon carbide layer thickness on the passivation quality of crystalline silicon surface , 2005 .

[5]  Richard M. Swanson,et al.  Light‐induced degradation at the silicon/silicon dioxide interface , 1988 .

[6]  M. Green,et al.  24.5% efficiency PERT silicon solar cells on SEH MCZ substrates and cell performance on other SEH CZ and FZ substrates , 2001 .

[7]  W. Füssel,et al.  Defects at the Si/SiO2 interface: Their nature and behaviour in technological processes and stress , 1996 .

[8]  M. Taguchi,et al.  HITTM cells—high-efficiency crystalline Si cells with novel structure , 2000 .

[9]  Sbs Stephan Heil,et al.  In situ reaction mechanism studies of plasma-assisted atomic layer deposition of Al2O3 , 2006 .

[10]  Wmm Erwin Kessels,et al.  Ultralow surface recombination of c-Si substrates passivated by plasma-assisted atomic layer deposited Al2O3 , 2006 .

[11]  Wmm Erwin Kessels,et al.  Low-Temperature Deposition of TiN by Plasma-Assisted Atomic Layer Deposition , 2006 .

[12]  M. M. Shahin.  Mass‐Spectrometric Studies of Corona Discharges in Air at Atmospheric Pressures , 1966 .

[13]  Jan Benick,et al.  High efficiency n-type Si solar cells on Al2O3-passivated boron emitters , 2008 .

[14]  Sun Jin Yun,et al.  Electrical Properties of Alumina Films by Plasma-Enhanced Atomic Layer Deposition , 2004 .

[15]  Wmm Erwin Kessels,et al.  Surface passivation of high‐efficiency silicon solar cells by atomic‐layer‐deposited Al2O3 , 2008 .

[16]  G. Beaucarne,et al.  Surface passivation properties of boron-doped plasma-enhanced chemical vapor deposited hydrogenated amorphous silicon films on p-type crystalline Si substrates , 2006 .

[17]  R. Mertens,et al.  Determination of Si-SiO/sub 2/ interface recombination parameters using a gate-controlled point-junction diode under illumination , 1988 .

[18]  M. Schulz,et al.  Space-charge region-dominated steady-state photoconductance in low-lifetime Si wafers , 2003 .

[19]  R. Alcubilla,et al.  Characterization of a-Si:H∕c-Si interfaces by effective-lifetime measurements , 2005 .

[20]  K. Bothe,et al.  Mapping of trap densities and energy levels in semiconductors using a lock-in infrared camera technique , 2005 .

[21]  M. Abbott,et al.  Self-consistent calibration of photoluminescence and photoconductance lifetime measurements , 2005 .

[22]  W. Warta,et al.  Field effect passivation of high efficiency silicon solar cells , 1993 .

[23]  D. Schroder.  Semiconductor Material and Device Characterization , 1990 .

[24]  Chang,et al.  Unusually low surface-recombination velocity on silicon and germanium surfaces. , 1986, Physical review letters.

[25]  A. Cuevas,et al.  Very low bulk and surface recombination in oxidized silicon wafers , 2002 .

[26]  Thomas Lauinger,et al.  Record low surface recombination velocities on 1 Ω cm p‐silicon using remote plasma silicon nitride passivation , 1996 .

[27]  K. McIntosh,et al.  Calibration of the WCT‐100 photoconductance instrument at low conductance , 2008 .

[28]  W. Warta,et al.  Field-effect passivation of the SiO2Si interface , 1999 .

[29]  Eugene A. Irene,et al.  Handbook of Ellipsometry , 2005 .

[30]  Mark Kerr,et al.  Recombination at the interface between silicon and stoichiometric plasma silicon nitride , 2002 .

[31]  M. Kunst,et al.  Recombination at the silicon nitride/silicon interface , 1997 .

[32]  A. Cuevas,et al.  General parameterization of Auger recombination in crystalline silicon , 2002 .

[33]  Wilhelm Warta,et al.  Impact of illumination level and oxide parameters on Shockley–Read–Hall recombination at the Si‐SiO2 interface , 1992 .

[34]  P. Altermatt,et al.  Excellent passivation of highly doped p-type Si surfaces by the negative-charge-dielectric Al2O3 , 2007 .

[35]  Harold Dekkers,et al.  Very low surface recombination velocities on p-type silicon wafers passivated with a dielectric with fixed negative charge , 2006 .

[36]  Christophe Ballif,et al.  Model for a-Si: H/c-Si interface recombination based on the amphoteric nature of silicon dangling bonds , 2007 .

[37]  Armin G. Aberle,et al.  Progress in Low‐temperature Surface Passivation of Silicon Solar Cells using Remote‐plasma Silicon Nitride , 1997 .

[38]  Paul A. Basore,et al.  Numerical modeling of textured silicon solar cells using PC-1D , 1990 .

[39]  Rudolf Hezel,et al.  Experimental evidence of parasitic shunting in silicon nitride rear surface passivated solar cells , 2002 .

[40]  D. Macdonald,et al.  Trapping of minority carriers in multicrystalline silicon , 1999 .

[41]  J. Cotter,et al.  Passivation of boron emitters on n-type silicon by plasma-enhanced chemical vapor deposited silicon nitride , 2006 .

[42]  R. Sinton,et al.  Contactless determination of current–voltage characteristics and minority‐carrier lifetimes in semiconductors from quasi‐steady‐state photoconductance data , 1996 .

[43]  D. Neuhaus,et al.  Experimental verification of the effect of depletion-region modulation on photoconductance lifetime measurements , 2004 .

[44]  Simon D. Elliott,et al.  Ozone-Based Atomic Layer Deposition of Alumina from TMA: Growth, Morphology, and Reaction Mechanism , 2006 .

[45]  W. Kern.  The Evolution of Silicon Wafer Cleaning Technology , 1990 .

[46]  V. Mihailetchi,et al.  Nitric acid pretreatment for the passivation of boron emitters for n-type base silicon solar cells , 2008 .

[47]  Wmm Erwin Kessels,et al.  Plasma and thermal ALD of Al2O3 in a commercial 200 mm ALD reactor , 2007 .

[48]  Sbs Stephan Heil,et al.  Deposition of TiN and HfO2 in a commercial 200 mm remote plasma atomic layer deposition reactor , 2007 .

[49]  D. Aspnes,et al.  Optical-standard surfaces of single-crystal silicon for calibrating ellipsometers and reflectometers. , 1994, Applied optics.

[50]  R. Hezel,et al.  Low‐Temperature Surface Passivation of Silicon for Solar Cells , 1989 .