The Stability of Thin Interfacial SiO2 Layers in Directly Bonded Czochralski and Float‐Zone Silicon Wafer Pairs

Li, Ling; Shimura, Fumio

doi:10.1149/1.2056098

Cited by 16 publications

(5 citation statements)

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“…[1][2][3][4] SiO 2 films can be deposited by evaporation, sputtering, sol-gel, chemical vapor deposition, and other methods. [1][2][3][4] SiO 2 films can be deposited by evaporation, sputtering, sol-gel, chemical vapor deposition, and other methods.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of SiO2 films with different techniques

Zhang

1998

Journal of Elec Materi

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Section: Introductionmentioning

confidence: 99%

Preparation and characterization of SiO2 films with different techniques

Zhang

1998

Journal of Elec Materi

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“…SOI substrates fabricated by SIMOX (separation by implanted oxygen) are typically subjected to internal thermal oxidation (ITOX) anneals to thicken buried oxides formed by high dose oxygen ion implantation (6,7). In the context of Si wafer bonding, the thermal stability of thin (1 -10 nm) interfacial oxides between bonded wafer surfaces has been examined as a function of Si wafer doping, Si wafer growth method (float-zone (FZ) or Czochralski (Cz)), and Si wafer surface orientation (7)(8)(9)(10). It was concluded that dissolution of native oxides having a thickness >1 nm is not possible with annealing at temperatures in the range 1100 -1200 o C, and that undesirable oxide islanding is typical, especially with Cz wafers.…”

Section: Introductionmentioning

confidence: 99%

Mixed Orientation Si-Si Interfaces by Hydrophilic Bonding and High Temperature Oxide Dissolution: Wafer Fabrication Technique and Device Applications

Saenger¹,

Souza²,

Fogel³

et al. 2007

ECS Trans.

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In this paper we describe a quasi-hydrophobic bonding method in which ultrathin (<1-2 nm) oxide present on wafer surfaces during bonding is removed after bonding by a high-temperature oxide dissolution anneal to leave the desired direct Si-to-Si contact at the bonded interface. We will show that the direct- silicon-bonded (DSB) interfaces produced by this method are clean enough to allow implementation of a recently described amorphization/templated recrystallization technique for changing the orientation of selected DSB layer regions from their original orientation to the orientation of the underlying handle wafer, and then discuss some of the mechanisms and integration challenges associated with wafer and device fabrication by these techniques.

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“…6,7 In the context of Si wafer bonding, the thermal stability of thin ͑1-10 nm͒ interfacial oxides between bonded wafer surfaces has been examined as a function of Si wafer doping, Si wafer growth method ͓float-zone ͑FZ͒ or Czochralski ͑CZ͔͒, and Si wafer surface orientation. [7][8][9][10] It was concluded that dissolution of native oxides having a thickness Ͼ1 nm is not possible with annealing at temperatures in the range of 1100-1200°C and that undesirable oxide islanding is typical, especially with CZ wafers. In con-trast to these results, it was shown 4 that a few monolayers of interfacial oxide could be made to disappear in FZ wafers after annealing at 1150°C.…”

mentioning

confidence: 99%

Mixed Orientation Si–Si Interfaces by Hydrophilic Bonding and High Temperature Oxide Dissolution

Saenger

Souza

Fogel

et al. 2008

J. Electrochem. Soc.

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In this paper, we describe a "quasi-hydrophobic" bonding method in which ultrathin ͑Ͻ1-2 nm͒ oxide, present on wafer surfaces during bonding, is removed after bonding by a high temperature oxide dissolution anneal to leave the desired direct Si-to-Si contact at the bonded interface. We show that the direct-silicon-bonded ͑DSB͒ interfaces produced by this method are clean enough to allow implementation of a recently described amorphization/templated recrystallization technique for changing the orientation of selected DSB layer regions from their original orientation to the orientation of the underlying handle wafer. We then present results from a related study on the dissolution of oxide layers disposed between a Si substrate and a polycrystalline overlayer, and discuss mechanisms most likely to be operative for our oxide dissolution observations. Semiconductor device technology is increasingly relying on bonded Si wafer substrates to achieve desired performance targets. Most Si wafer bonding is hydrophilic, between wafer surfaces that are oxidelike. Hydrophilic bonding is clearly the technique of choice when an oxide is desired at the bonded interface, for example, when fabricating silicon-on-insulator ͑SOI͒ structures. However, certain fabrication schemes for bulk hybrid orientation substrates 1,2 require a direct Si-to-Si bond between Si surfaces having different surface orientations, with no oxide layer at the bonded interface.Direct Si-to-Si bonding for direct-silicon-bonded ͑DSB͒ wafers is normally achieved with hydrophobic bonding, 3 a technique with some difficulties. Hydrophobic ͑H-terminated͒ surfaces are more easily contaminated than hydrophilic ones, often making it necessary to perform the bonding in a vacuum environment. In addition, the widely used surface plasma treatments developed to allow roomtemperature bonding, typically, though with some exceptions, 4 introduce surface oxygen, making them incompatible with an oxide-free bonded interface. Bonding at higher temperatures can also present difficulties because most cleaving processes for separating the bonded layer from the wafer to which it was originally attached are thermally activated and start occurring in the same temperature range as the bonding. Given these difficulties, it was thought that it might be preferable to fabricate DSB wafers with a "quasihydrophobic" bonding technique in which an ultrathin ͑1-2 nm͒ oxide would be present on one or both wafer surfaces during bonding ͑thereby allowing the bonding to be hydrophilic͒, but removed after the bonding ͑to leave the desired direct Si-to-Si contact at the bonded interface͒.The stability of buried oxide layers in Si is a topic with relevance to both Si-based devices 5 ͑due to the need for tightly controlled thicknesses of thin insulating SiO 2 layers between electrically active Si regions͒ and silicon-on-insulator ͑SOI͒ substrate fabrication. SOI substrates fabricated by separation by implanted oxygen ͑SIMOX͒ are typically subjected to internal thermal oxidation ͑ITOX͒ anneals to thicken ...

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The Stability of Thin Interfacial SiO2 Layers in Directly Bonded Czochralski and Float‐Zone Silicon Wafer Pairs

Cited by 16 publications

References 0 publications

Preparation and characterization of SiO2 films with different techniques

Preparation and characterization of SiO2 films with different techniques

Mixed Orientation Si-Si Interfaces by Hydrophilic Bonding and High Temperature Oxide Dissolution: Wafer Fabrication Technique and Device Applications

Mixed Orientation Si–Si Interfaces by Hydrophilic Bonding and High Temperature Oxide Dissolution

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