Effect of Plasma Pretreatment on Fixed Charge at the Silicon Nitride/Silicon Interface

Takakura, Tomoyuki; Imai, R.; Okamoto, Yuka; Taniguchi, Hiroshi

doi:10.1143/jjap.49.046502

Cited by 6 publications

(5 citation statements)

References 14 publications

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“…Above 425 1C silicon nitride is formed at the Si surface whose formation increases with temperature. That this nitridation has indeed a direct relation with Q f was shown by Takakura, though he did not observe a difference in D it [8].…”

Section: Introductionmentioning

confidence: 76%

Interface properties of a-SiNx:H/Si to improve surface passivation

Lamers¹,

Butler²,

Harding³

et al. 2012

Solar Energy Materials and Solar Cells

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Nitridation is the process in which, during the initial growth of a-SiN x :H layers on Si surfaces, nitrogen is incorporated into the Si lattice near its surface. We show that this nitridation process affects the density of interface states (D it) and fixed charges (Q f) at the interface. These parameters determine the effective surface passivation quality of the layers. The nitridation can be tuned independently of the growth of a-SiN x :H layers by using a plasma treatment prior to actual a-SiN x :H layer deposition. It is shown that Q f can be varied from 2 Â 10 12 to 15 Â 10 12 cm À 2 without changing the a-SiN x :H deposition process. It is demonstrated that in our case and processing window, Q f is the determining factor in surface passivation quality in the range of 2 Â 10 12 to 8 Â 10 12 cm À 2. For higher values of Q f , D it has increased significantly and has become dominant thereby reducing the passivation quality. It is shown that the passivation can be controlled independently of the a-SiN x :H deposition process. In completed solar cells the effect of the controlled Q f and D it is studied. On n-type solar cells, due to increased depletion, increases in Q f and D it resulted in a drop in open-circuit voltage, V oc , of over 20 mV. On p-type solar cells, where the Q f results in accumulation, the effect was negligible.

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Section: Introductionmentioning

confidence: 76%

Interface properties of a-SiNx:H/Si to improve surface passivation

Lamers¹,

Butler²,

Harding³

et al. 2012

Solar Energy Materials and Solar Cells

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show abstract

“…It has been shown in the past that the interface properties and the fixed charge density are a sensitive function of the ammonia pre-treatment parameters [19]. It was demonstrated recently that the plasma pre-treatment on ptype (1 1 1) Si reduces the D it , irrespective of the source gases, whereas the fixed charge at the SiN x /Si interface depends on the stoichiometry of the thin nitrided layer [20]. From the above, it can be concluded that further studies are required to optimize the ammonia pre-treatment for planar (1 1 1) and textured n-type SiN x /Si interfaces.…”

Section: Discussionmentioning

confidence: 99%

Study of silicon-silicon nitride interface properties on planar (1 0 0), planar (1 1 1) and textured surfaces using deep-level transient spectroscopy

Gong

Simoen

Posthuma

et al. 2010

J. Phys. D: Appl. Phys.

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Deep-level transient spectroscopy (DLTS) has been applied to metal–insulator–semiconductor (MIS) capacitors fabricated on planar (1 0 0), planar (1 1 1) orientations and textured n-type silicon wafers. Low frequency direct plasma-enhanced chemical vapour deposition Si–SiN x interface properties with and without plasma NH3 pre-treatment, with and without rapid thermal annealing (RTA) have been investigated. It is shown that three different kinds of defect states are identified at the Si–SiN x interface. For the planar (1 0 0) surface, samples with plasma NH3 pre-treatment plus RTA show the lowest DLTS signals, which suggests the lowest overall interface states density. For planar (1 1 1) Si surfaces, plasma NH3 pre-treatment and RTA yield a small improvement. With the textured surface, the RTA step improves the surface passivation quality further but no obvious impact is found with plasma NH3 pre-treatment. Energy-dependent electron capture cross sections were also measured by small-pulse DLTS. The capture cross sections depend strongly on the energy level and decrease towards the conduction band edge.

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“…The optimal value of x and hence n, is very dependent upon the type of solar cell, the optimal wavelength, the texture, the module fabrication etc, for example in air a value of n=1.9 is optimal, however generally in solar cells in modules values of n = 2.04 -2.08 are preferred 7,8 .…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics studies of the bonding properties of amorphous silicon nitride coatings on crystalline silicon

Butler

Lamers

Weeber

et al. 2011

Journal of Applied Physics

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In this paper we present molecular dynamics simulations of silicon nitride, both in bulk and as an interface to crystalline silicon. We investigate, in particular, the bonding structure of the silicon nitride and analyze the simulations to search for defective geometries which have been identified as potential charge carrier traps when silicon nitride forms an interface with silicon semiconductors. The simulations reveal how the bonding patterns in silicon nitride are dependent upon the stoichiometry of the system. Furthermore we demonstrate how having an "interphase", where the nitrogen content in silicon gradually reduces towards pure silicon across a boundary region, as opposed to an interface where there is an abrupt drop in nitrogen concentration at the boundary, can result in significantly different numbers of certain important carrier trap

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Effect of Plasma Pretreatment on Fixed Charge at the Silicon Nitride/Silicon Interface

Cited by 6 publications

References 14 publications

Interface properties of a-SiNx:H/Si to improve surface passivation

Interface properties of a-SiNx:H/Si to improve surface passivation

Study of silicon-silicon nitride interface properties on planar (1 0 0), planar (1 1 1) and textured surfaces using deep-level transient spectroscopy

Molecular dynamics studies of the bonding properties of amorphous silicon nitride coatings on crystalline silicon

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