Atomic layer controlled deposition of silicon nitride with self-limiting mechanism

Okuno, Hiroshi G.; Shibahara, Kentaro; Yokoyama, Shiyoshi

doi:10.1063/1.116566

Cited by 92 publications

(55 citation statements)

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“…vestigate the adsorption and decomposition of ammonia in a temperature range of 300-800 K. This span is particularly interesting because most modern applications require moderate temperature regimes, not only to produce ultrathin films through atomic layer deposition [56][57][58] but also as a way to functionalize the semiconductor surface for applications in molecular electronics and design of self-assembled surface structures. 59,60 The results and their interpretation are divided into three sections.…”

Section: Introductionmentioning

confidence: 99%

Cooperative nitrogen insertion processes: Thermal transformation ofNH3on a Si(100) surface

Rodríguez‐Reyes

Teplyakov

2007

Phys. Rev. B

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The thermal behavior of an ammonia-covered Si͑100͒ surface is investigated by infrared spectroscopy and density functional methods. Upon adsorption at room temperature, ͑Si͒NH 2 and Si-H species are formed on the surface. Comparison of the vibrational studies with density functional calculations suggests that the ͑Si͒NH 2 structures are preferentially located on the same side along the silicon dimer row on a ͑2 ϫ 1͒ reconstructed Si͑100͒ surface, although a mixture of different long-range configurations is likely formed. Decomposition of these ͑Si͒NH 2 species is observed to start at temperatures as low as 500 K. Theoretical predictions of the vibrational modes indicate that at this point, the spectrum is composed of a combination of ͑Si͒ 2 NH and ͑Si͒ 3 N vibrational signatures, which result from insertion of N into Si-Si bonds. Our computational study of the formation of ͑Si͒ 2 NH structures indicates that subsurface insertion is more feasible if the strain imposed during the insertion in a Si dimer is attenuated by a ͑Si͒ 2 NH structure already inserted in the neighboring dimer along the same silicon dimer row. This cooperative reaction lowers the energetic requirements for subsurface insertion, providing a theoretical explanation for the mechanism of thermal decomposition of NH 3 on Si͑100͒ and for other systems where subsurface migration is observed experimentally.

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Section: Introductionmentioning

confidence: 99%

Cooperative nitrogen insertion processes: Thermal transformation ofNH3on a Si(100) surface

Rodríguez‐Reyes

Teplyakov

2007

Phys. Rev. B

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“…Further, the processing requirements of modern logic at the smallest technology nodes additionally have a stringent thermal budget such that depositions should be performed at as low of a temperature as possible and at least below 450 • C. More than a decade ago, early work in SiN x thermal ALD and PEALD were shown with various chlorosilanes and nitridation reactants such as ammonia or hydrazine. [4][5][6] These depositions have generally required processing at temperatures above the thermal budget of current processes and have the added disadvantage of Cl residues and byproducts from the reactions. PEALD of SiN x based on SiH 4 has also been explored to avoid the Cl contamination issue, but while this can maintain desired temperature range, the reaction requires extensive SiH 4 exposure in both time and gas flow.…”

Section: Introductionmentioning

confidence: 99%

Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

et al. 2016

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The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiNx), particularly for use a low k dielectric spacer. One of the key material properties needed for SiNx films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiNx and evaluate the film’s WER in 100:1 dilutions of HF in H2O. The remote plasma capability available in PEALD, enabled controlling the density of the SiNx film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiNx of 6.1 Å/min, which is similar to WER of SiNx from LPCVD reactions at 850 °C.

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“…[1][2][3][4] The processing requirements of modern logic processors at the smallest technology nodes additionally have a stringent thermal budget such that depositions should be performed at as low of a temperature as possible and at least below 450 °C. More than a decade ago, earlier works in SiN thermal atomic layer deposition (T-ALD) and plasma enhanced atomic layer deposition (PEALD) were reported with dichlorosilane (SiH 2 Cl 2 ) as well as co-reactants for nitridation such as ammonia or hydrazine: [5][6][7] Dichlorosilane (DCS), however, has generally required processing at >750 o C for thermally-mediated processes and an alternative PEALD route yields films with lower density (~2.6 g/cm 3 ) and unwanted Cl residue (~0.5 at%), which may require high temperature posttreatment for its elimination. PEALD of SiN based on silane (SiH 4 ) has also been explored to avoid the Cl contamination issue, but while this has been demonstrated, the reactant volumes and times are excessive and WER values are insufficient for process needs.…”

Section: Introductionmentioning

confidence: 99%

Plasma-Enhanced Atomic Layer Deposition of SiN–AlN Composites for Ultra Low Wet Etch Rates in Hydrofluoric Acid

Kim¹,

Provine²,

Walch³

et al. 2016

ACS Appl. Mater. Interfaces

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The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposited (ALD) of hydrofluoric acid (HF) etch resistant and electrically insulating films for sidewall spacer processing. Silicon nitride (SiN) has been the prototypical material for this need and extensive work has been conducted into realizing sufficiently lower wet etch rates (WERs) as well as leakage currents to meet industry needs. In this work, we report on the development of plasma-enhanced atomic layer deposition (PEALD) composites of SiN and AlN to minimize WER and leakage current density. In particular, the role of aluminum and the optimum amount of Al contained in the composite structures have been explored. Films with near zero WER in dilute HF and leakage currents density similar to pure PEALD SiN films could be simultaneously realized through composites which incorporate ≥13 at. % Al, with a maximum thermal budget of 350 °C.

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Atomic layer controlled deposition of silicon nitride with self-limiting mechanism

Cited by 92 publications

References 0 publications

Cooperative nitrogen insertion processes: Thermal transformation ofNH3on a Si(100) surface

Cooperative nitrogen insertion processes: Thermal transformation ofNH3on a Si(100) surface

Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

Plasma-Enhanced Atomic Layer Deposition of SiN–AlN Composites for Ultra Low Wet Etch Rates in Hydrofluoric Acid

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