Hydrogen-induced boron passivation in Cz Si

Castaldini, A.; Cavalcoli, Daniela; Cavallini, A.; Susi, E.

doi:10.1007/s003390101067

Cited by 8 publications

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“…In a previous study on the same material, [5][6][7] we observed that the B deactivation, as well as the trap, disappeared after annealing at temperatures above 200°C, and proposed hydrogen as responsible of the deactivation as well as of the trap. Hydrogen is released at the Si surface by all the standard cleaning and etching treatments, diffuses even at room temperature up to 2-3 mm form the surface, and usually out-diffuses from Si at temperatures higher than 200°C ͑see Ref.…”

Section: Resultsmentioning

confidence: 87%

Surface Modifications in Si after Rapid Thermal Annealing

Castaldini¹,

Cavalcoli²,

Cavallini³

et al. 2002

J. Electrochem. Soc.

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The results of an investigation of the impact of rapid thermal annealing ͑RTA͒ at two different temperatures, 750 and 1050°C, on the electrical behavior and the morphology of a Si wafer surface are presented. A remarkable degradation of the surface and subsurface regions of Si wafers is detected after the RTA: the maximum electrical damage is observed after the 750°C anneal, while surface roughening is induced by the 1050°C anneal. Several mechanisms responsible for the observed changes in the electrical and morphological wafer characteristics are discussed.Rapid thermal annealing ͑RTA͒ is currently used in microelectronics technology for a number of process steps such as dopant activation, silicidation, and reflow of dielectric layers. New interest in this technique has been prompted by the possibility for growth of very thin dielectric layers as the gate oxide of the metal oxide semiconductor ͑MOS͒ transistors. As a consequence an increasing number of studies has been devoted to investigating the impact of RTA on device performance. 1-4 A number of studies outline the importance of the changes induced in the Si substrate surface and, in particular, annealing-induced roughening. 2,3 However, the microscopic mechanisms controlling these surface modifications in the Si wafers have still to be understood.The present study is an investigation of the impact of RTA at two different temperatures, 750 and 1050°C, on the electrical behavior and the morphology of a Si wafer surface. Capacitance-voltage ͑C-V͒ and current-voltage ͑I-V͒ characteristics of Schottky diodes deposited on the as-annealed samples, minority carrier diffusion length, and surface recombination velocity measurements, electron beam induced current ͑EBIC͒, and deep level transient spectroscopy ͑DLTS͒ monitored the changes in the electrical parameters; the changes in the surface structural properties were detected by atomic force microscopy ͑AFM͒. The correlation of the electrical and structural data was used to identify some of the processes induced by thermal annealing at the wafer surface. Experimental200 mm ͑100͒ B-doped, resistivity 12 ⍀ cm, Czochralski Si wafers from MEMC, Novara, Italy, were used. The anneals at 750 and 1050°C for 60 s were performed in a commercial AG Associates heat pulse lamp system: the ambient gas was Ar. The ramp up and ramp down of the RTA cycles were of the order of 200 and 80°C/s, respectively. No surface treatment was performed on the samples prior to the RTA step.Special attention was given to the preparation of the Schottky diodes: they were realized by high purity Al evaporation on samples cut from different areas of the wafers. A purposely made Al mask was used to define the Schottky diode structure. This evaporation was performed without any previous surface treatment: no HF etching was done on the as-received surfaces in order to avoid any modification of the surface structure. Ohmic contact was made by scratching the back surface and wetting it with an Hg-In amalgam. The samples were mounted on a purposely made ho...

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Section: Resultsmentioning

confidence: 87%

Surface Modifications in Si after Rapid Thermal Annealing

Castaldini¹,

Cavalcoli²,

Cavallini³

et al. 2002

J. Electrochem. Soc.

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“…All the data presented above provide clear evidence that hydrogen induced a decrease in the FeB deep level. A significant proportion of the boron concentration is neutralized in the surface region after wet chemical etching (Adegboyega et al, 1989;Castaldini et al, 2002). We find an almost and for different times.…”

Section: Dlts Measurementsmentioning

confidence: 58%

“…Carrier depth profiles are necessary to investigate the incorporation of hydrogen in silicon samples. For example, previous studies have calculated boron depth profiles from the CV measurements after wet chemical etching, reporting a decrease on the surface of the sample as well as complete recovery of boron at 2.5µm depths as seen from figure 4.2 (Adegboyega et al, 1989;Castaldini et al, 2002). The boron passivation incorporated from the surface.…”

Section: 1 CV Measurementsmentioning

confidence: 94%

“…From CV measurements, the capacitance at the DLTS reverse bias voltage, the built-in voltage and the shallow acceptor concentration were obtained. Sullivan et al, 1993;Castaldini et al, 2002), and attributed to It is not possible to measure lower concentration of hydrogen in silicon by the rogen profile traditional analytical techniques. However, higher concentrations of hydrogen more than 10 17 cm -3 are chemically detectable.…”

Section: 1 CV Measurementsmentioning

confidence: 99%

“…The longer the etching time, the more boron are passivated. It is generally believed that this decrease in boron is compensated by the formation of boron hydrogen pair and a rough estimate (Adegboyega et al, 1989;Castaldini et al, 2002).…”

Section: 1 CV Measurementsmentioning

confidence: 99%

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Concentrations and Reactions of Iron in Crystalline Silicon after Aluminum Gettering

Barey¹,

Othman²

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Iron is the most common transition metal impurities in semiconductor industry and PV silicon. Thus, it seems unlikely to avoid contamination with iron that has been considered to have the highest concentration in silicon wafers (Jastrzebski, et al., 1995). Unfortunately, less than 1ppb of iron was found to degrade the performance of p-type silicon device through the massive reduction of the minority carrier diffusion length (Buonassisi et al., described. Results and discussion are included in chapter 4. This chapter is divided into four parts; the influence of wet chemical etching on the iron concentration in silicon as well as the correspondence between time of etching, different etchants and boron passivation profile are studied in the first part. The second part deals with the aluminum gettering of iron in silicon and the physical mechanisms relevant for such temperature-dependent segregation coefficient in order to increase the understanding of the abilities and limitations of aluminum gettering in silicon solar cell processing, while the third part treats various aspects of aluminum gettering induced vacancies and using several ways to monitor vacancy concentration such as platinum and gold diffusion. Based on these finding, the last part in this thesis investigates the interaction between iron and induced vacancies from aluminum gettering under light illumination. Particular attention is devoted to gettering of iron and the interplay with vacancy, as well as to the influence of light on the formation of iron vacancy complexes (FeD). Finally, the main ideas of the thesis are summarized along a short conclusion and outlook in chapter 5.

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Comparison of In doped and In, Pb co-doped Cd0.9Zn0.1Te

Zaman

Wang

et al. 2015

Nuclear Instruments and Methods in Physics Research Section A:

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Hydrogen-induced boron passivation in Cz Si

Cited by 8 publications

References 0 publications

Surface Modifications in Si after Rapid Thermal Annealing

Surface Modifications in Si after Rapid Thermal Annealing

Concentrations and Reactions of Iron in Crystalline Silicon after Aluminum Gettering

Comparison of In doped and In, Pb co-doped Cd0.9Zn0.1Te

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