Impact of ultraviolet light during rapid thermal diffusion

Noël, S.; Slaoui, A.; Müller, J. C.; Groh, Benjamin H.; Schindler, R.; Fröschle, B.; Theiler, T.

doi:10.1063/1.121425

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…It is also possible that the ultraviolet (UV)/vacuum ultraviolet (VUV) radiation from the plasma or the synergy of impinging ions and UV/VUV radiation assists with oxygen diffusion. 26…”

Section: Ion-enhanced Diffusion Of Oxygen Through the Surface Oxidmentioning

confidence: 99%

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Fukasawa¹,

Nakakubo

Matsuda

et al. 2011

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Silicon substrate damage caused by HBr/O 2 plasma exposure was investigated by spectroscopic ellipsometry (SE), high-resolution Rutherford backscattering spectroscopy, and transmission electron microscopy. The damage caused by H 2 , Ar, and O 2 plasma exposure was also compared to clarify the ion-species dependence. Although the damage basically consists of a surface oxidized layer and underlying dislocated Si, the damage structure strongly depends on the incident ion species, ion energy, and oxidation during air and plasma exposure. In the case of HBr/O 2 plasma exposure, hydrogen generated the deep damaged layer ($10 nm), whereas ion-enhanced diffusion of oxygen, supplied simultaneously by the plasma, caused the thick surface oxidation. In-line monitoring of damage thicknesses by SE, developed with an optimized optical model, showed that the SE can be used to precisely monitor damage thicknesses in mass production. Capacitance-voltage (C-V) characteristics of a damaged layer were studied before and after diluted-HF (DHF) treatment. Results showed that a positive charge is generated at the surface oxide-dislocated Si interface and/or in the bulk oxide after plasma exposure. After DHF treatment, most of the positive charges were removed, while the thickness of the "Si recess" was increased by removing the thick surface oxidized layer. As both the Si recess and remaining dislocated Si, including positive charges, cause the degradation of electrical performance, precise monitoring of the surface structure and understanding its effect on device performance is indispensable for creating advanced devices. V

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“…It is also possible that the ultraviolet (UV)/vacuum ultraviolet (VUV) radiation from the plasma or the synergy of impinging ions and UV/VUV radiation assists with oxygen diffusion. 26…”

Section: Ion-enhanced Diffusion Of Oxygen Through the Surface Oxidmentioning

confidence: 99%

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Fukasawa¹,

Nakakubo

Matsuda

et al. 2011

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…2 Experimentation with a combination of incandescent and mercury vapor lamps has indicated an increase in dopant diffusion under ultraviolet illumination. 3 Formation of shallow junctions from phosphorus surface diffusion was found to be affected also by exposure to vacuum ultraviolet photons (wavelength k < 200 nm). 4 Photonic effects have been studied in a variety of annealing experiments, 5,6 including the electrical activation and diffusion of n-type dopants in crystalline silicon.…”

Section: Introductionmentioning

confidence: 98%

Photothermal Activation of Shallow Dopants Implanted in Silicon

Fiory

Stevenson

Agarwal³

et al. 2007

Journal of Elec Materi

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Dopant impurities were implanted at high dose and low energy (10 15 cm -2 , 0.5-2.2 keV) into double-side polished 200 mm diameter silicon wafers and electrically activated to form p-n junctions by 10 s anneals at temperatures of 1,025, 1,050, and 1,075°C by optical heating with tungsten incandescent lamps. Activation was studied for P, As, B, and BF 2 species implanted on one wafer side and for P and BF 2 implanted on both sides of the wafer. Measurements included electrical sheet resistance (Rs) and oxide film thickness. A heavily boron-doped wafer, which is optically opaque, was used as a hot shield to prevent direct exposure to lamp radiation on the adjacent side of the test wafer. Two wafers with opposing orientations with respect to the shield wafer were annealed for comparison of exposure to, or shielding from, direct lamp illumination. Differences in sheet resistance for the two wafer orientations ranged from 4% to 60%. n-Type dopants implanted in p-type wafers yielded higher Rs when the implanted surface was exposed to the lamps, as though the effective temperature had been reduced. p-Type dopants implanted in ntype wafers yielded lower Rs when the implanted surface was exposed to the lamps, as though the effective temperature had been increased. Effective temperature differences larger than 5°C, which were observed for the P, B, and BF 2 implants, exceeded experimental uncertainty in temperature control.

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“…This allows well-defined processing at elevated temperatures even for extremely short duration times in the range of a few seconds. Furthermore, several authors have observed an acceleration of diffusion and oxidation processes which they attribute to the significant proportion of high energy photons contained in the incident electromagnetic spectrum [1][2][3]. In summary these advantages account for a reduction in the total process time from 10 3 s down to 10 1 s, that is of about two orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

Record fast thermal processing of 17.5 efficient silicon solar cells

Peters

Ballif

Borchert

et al. 2002

Semicond. Sci. Technol.

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This paper presents the development and analysis of 17.5% efficient silicon solar cells on 0.9 cm PV-grade Czochralski silicon (Cz-Si), featuring a record small thermal process time of 1 min for diffusion and oxidation. The cells have been processed by rapid thermal processing (RTP) using incoherent light as an energy source. The involved processes consist of a 5 s RTP step at 930 • C for the simultaneous formation of the phosphorus-doped emitter and of the aluminium back surface field (Al-BSF) and a 30 s rapid thermal oxidation (RTO) at 950 • C for the emitter surface passivation. Both processes feature high heating and cooling rates of 100 K s −1 . The results show that no lengthy gettering or post diffusion annealing steps are required for the fabrication of high efficiency Cz-Si solar cells and that high heating and cooling rates are applicable. Detailed analysis reveals that the emitter saturation current J 0e is reduced by a factor of 3-4 after the RTO passivation in spite of the high carrier surface concentrations of 3 to 4 × 10 20 cm −3 . Furthermore, one-dimensional device simulations are presented which show that the achieved efficiencies are limited by the effective back surface recombination velocity S back resulting from the thin Al-BSF applied.

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Impact of ultraviolet light during rapid thermal diffusion

Abstract: Impact of metal silicide precipitate dissolution during rapid thermal processing of multicrystalline silicon solar cells

Cited by 9 publications

References 11 publications

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Photothermal Activation of Shallow Dopants Implanted in Silicon

Record fast thermal processing of 17.5 efficient silicon solar cells

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