Drastic reduction in surface recombination velocity of crystalline silicon by surface treatment using catalytically-generated radicals

AbstractThis paper presents a measurement technique for studying of the interface between a nanocrystalline silicon (nc-Si) film and a crystalline silicon (c-Si) substrate using microwave photoconductivity decay (MWPCD). The nc-Si films were deposited using plasma enhanced chemical vapor deposition of highly hydrogen-diluted silane. The films were deposited on both sides of the high purity float-zone (FZ) Si wafers. The high resolution transmission electron microscope (HRTEM) analysis of the interface and the characterization of the effective excess carrier lifetime of the samples using MWPCD revealed the following results: (i) The crystallinity of the deposited nc-Si films is very high. The nc-Si film follows the crystal orientation of the substrate such that not a well-defined boundary between nc-Si film and the c-Si substrate is observed. (ii) A surface recombination velocity of less than 10 cm/s was measured for the interface region of the nc-Si/c-Si junctions. (iii) A small discontinuity in the band-energy diagram of the interface region was observed.

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Minority Carrier Annihilation at Crystalline Silicon Interface in Metal Oxide Semiconductor Structure

MRS Proceedings ◽

10.1557/opl.2014.921 ◽

2014 ◽

Vol 1666 ◽

Cited By ~ 1

Author(s):

Jun Furukawa ◽

Satoshi Shigeno ◽

Shinya Yoshidomi ◽

Tomohito Node ◽

Masahiko Hasumi ◽

...

Keyword(s):

Metal Oxide ◽

Minority Carrier ◽

Crystalline Silicon ◽

Surface Recombination ◽

Depletion Region ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Surface Recombination Velocity ◽

Light Illumination ◽

Recombination Velocity

ABSTRACTWe report photo induced minority carrier annihilation at the silicon surface in a metal–oxide–semiconductor (MOS) structure using 9.35 GHz microwave transmittance measurement. 7 Ωcm n-type 500-μm-thick crystalline silicon substrate coated with 100-nm-thick thermally grown SiO2 layers was used. 0.2-cm-long Al electrode bars were formed at the top and rear surfaces. 635 nm light illumination onto the top surface caused photo induced carriers to be in one side of the silicon region of the Al electrode. Microwave transmittance system detected photo induced carriers diffused from the light illuminated region via the MOS structured region. When the bias voltage was applied at +2.0 and -2.2 V to the electrode at the top surface, the surface recombination velocity increased from 44 (initial) to 83 and 86 cm/s, respectively because of depletion region formation at rear and top surface respectively. Those voltage applications caused change in the distribution of photo induced carriers in a 0.6-cm-wide region including light illuminated, MOS structured, microwave irradiated regions.

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Low-temperature Phosphorus Doping To Silicon Using Phosphorus-related Radicals

MRS Proceedings ◽

10.1557/opl.2012.526 ◽

2012 ◽

Vol 1391 ◽

Author(s):

Taro Hayakawa ◽

Yuuki Nakashima ◽

Koichi Koyama ◽

Keisuke Ohdaira ◽

Hideki Matsumura

Keyword(s):

Substrate Temperature ◽

Carrier Concentration ◽

Secondary Ion Mass Spectrometry ◽

Crystalline Silicon ◽

Surface Recombination ◽

Minority Carrier Lifetime ◽

Surface Recombination Velocity ◽

Passivation Layers ◽

Type C ◽

Recombination Velocity

ABSTRACTPhosphorus (P) doped ultra thin n+-layer is formed on crystalline silicon (c-Si) at low substrate temperatures of 80 – 350 °C using radicals generated by the catalytic reaction of phosphine (PH3) with a tungsten catalyzer heated at 1300 °C. The sheet carrier concentration obtained by Hall effect is in the range between 3×1012cm-2 and 8×1012cm-2. The distribution of P atoms obtained by secondary ion mass spectrometry (SIMS) indicates that P atoms locate within the depth of 4 nm from surface and the profile has almost the same distribution independent of any doping conditions such as substrate temperature or radical exposure time. The sheet carrier concentration is 1.15 – 2.12% of the amount of P atoms incorporated through the radical doping. The ratio of activated donors increases with substrate temperature during the radical doping, suggesting that P-related species bonded on the c-Si surface require thermal energy for their activation. Using the n+-layer formed by radical doping, the reduction of surface recombination velocity for n-type c-Si wafer is attempted. The effective minority carrier lifetime of the n-type c-Si sample covered with 6-nm-thick intrinsic amorphous Si (i-a-Si) layers on both side increases from 32 μs to1576 μs by the radical doping of P atoms to n-type c-Si surface, suggesting that the radical doping can be utilized for the formation of passivation layers on a-Si/ n-c-Si hetero-interface.

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Non-Destructive Method for Simultaneous Mapping of Diffusion Length and Surface Recombination Velocity

MRS Proceedings ◽

10.1557/proc-378-597 ◽

1995 ◽

Vol 378 ◽

Cited By ~ 1

Author(s):

Hans-Christoph Ostendorf ◽

Arthur L. Endrös

Keyword(s):

Diffusion Length ◽

Crystalline Silicon ◽

Surface Recombination ◽

Surface Recombination Velocity ◽

Silicon Solar Cells ◽

Crystalline Silicon Solar Cells ◽

Recombination Velocity ◽

Non Destructive ◽

Penetration Depths ◽

Main Material

AbstractBulk and surface recombination are the main material parameters that determine the performance of crystalline silicon solar cells. We present a new method for the nondestructive, simultaneous mapping of the diffusion length and the surface recombination velocity of a silicon wafer. The method uses the hardware of the electrolytical metal tracer (ELYMAT). The separation between bulk and surface recombination is achieved by illuminating the sample with laser beams of two different colors. By solving the diffusion equation for both laser penetration depths the diffusion length and the surface recombination velocity can be calculated from the measured diffusion currents. First experiments are presented which show the basic feasibility of the method.

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The Performance of Hg0.8Cd0.2Te Photodetectors by Using Photo Surface Treatment

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156497000287 ◽

1997 ◽

Vol 08 (04) ◽

pp. 703-717 ◽

Cited By ~ 1

Author(s):

Y. K. Su ◽

C. T. Lin

Keyword(s):

Surface Treatment ◽

Surface Recombination ◽

Chemical Vapor ◽

Lower Surface ◽

Treatment Method ◽

Cdte Layer ◽

Surface Recombination Velocity ◽

Noise Power ◽

Cdte Passivation ◽

Recombination Velocity

The principal aim of this paper is to propose an easy, vapor phase, and reproducible photo surface treatment method to improve the device performance of the Hg0.8Cd0.2Te photoconductive detector. Experimental results, including Auger electron spectroscopy (AES), MIS leakage current, 1/f noise voltage spectrum, 1/fknee frequency, responsivity Rλ, and specific detectivity D* for stacked photo surface treatment and ZnS or CdTe passivation layers are presented. By using this method, we found that there is no accumulation of Hg in the oxide/HgCdTe interface regions. Since the photo chemical vapor native oxidation is a dry oxidation method deposited at a low temperature, it can effectively suppress the Hg enhancement and the Cd depletion effects and thus obtain a high quality interface. We also found that the photo surface treatment in combination with thermally eveporated ZnS or CdTe layer would shift the 1/fknee under 100Hz in an electrical field under 50 V/cm, reduce the noise power spectrum, and achieve a lower surface recombination velocity S of 300 cm/sec as well as a high D* of 3 × 1010 cm [Formula: see text] for blackbody radiation. It was also found that HgCdTe photoconductor passivated with stacked layers shows improved interface properties when compared to the photoconductor passivated with a single passivation layer.

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