Comparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structures
Recently, to improve the performance of an integrated metal-oxide-semiconductor (MOS) device, an attempt has been made in the industry to replace the amorphous oxide with a crystalline oxide. However, various characteristics caused by the difference between amorphous and crystalline oxide in the MOS...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2022-01-01
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| Series: | Materials Research Express |
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| Online Access: | https://doi.org/10.1088/2053-1591/ac639f |
| _version_ | 1797746638953906176 |
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| author | Eunjung Ko Jung-Hae Choi |
| author_facet | Eunjung Ko Jung-Hae Choi |
| author_sort | Eunjung Ko |
| collection | DOAJ |
| description | Recently, to improve the performance of an integrated metal-oxide-semiconductor (MOS) device, an attempt has been made in the industry to replace the amorphous oxide with a crystalline oxide. However, various characteristics caused by the difference between amorphous and crystalline oxide in the MOS structure have not been systematically investigated. Therefore, we demonstrate the difference in atomic interface structures, electronic structures, and tunneling properties concerning varied oxide phases in a representative system, Si/SiO _2 /Si structures, with sub-3 nm-thick silica from first-principles. We investigate two oxide phases of amorphous ( a -) and crystalline ( c -) SiO _2 with and without H passivation at the interface. Si/ a -SiO _2 exhibits a smooth interface layer, whereas Si/ c -SiO _2 exhibits an abrupt interface layer, resulting in the thicker interface layer of Si/ a -SiO _2 than Si/ c -SiO _2 . Thus for a given total silica thickness, the adequate tunneling-blocking thickness, where all the Si atoms form four Si–O bonds, is thinner in a -SiO _2 than c -SiO _2 , originating more tunneling current through a -SiO _2 than c -SiO _2 . However, the effects of dangling bonds at Si/ c -SiO _2 rather than Si/ a -SiO _2 on tunneling currents are crucial, particularly in valence bands. Furthermore, when the dangling bonds are excluded by H atoms at Si/ c -SiO _2 , the tunneling current dramatically reduces, whereas the H-passivation effect on the tunneling blocking at Si/ a -SiO _2 is insignificant. Our study contributes systematic knowledge regarding oxide phases and interfaces to promote for high performance of MOS devices. |
| first_indexed | 2024-03-12T15:40:42Z |
| format | Article |
| id | doaj.art-ebe31cf073d348b0b1c187eee6f4a316 |
| institution | Directory Open Access Journal |
| issn | 2053-1591 |
| language | English |
| last_indexed | 2024-03-12T15:40:42Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Materials Research Express |
| spelling | doaj.art-ebe31cf073d348b0b1c187eee6f4a3162023-08-09T16:01:50ZengIOP PublishingMaterials Research Express2053-15912022-01-019404500510.1088/2053-1591/ac639fComparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structuresEunjung Ko0https://orcid.org/0000-0003-3427-4555Jung-Hae Choi1https://orcid.org/0000-0003-2956-6000Korea Institute for Advanced Study, Seoul 02455, Republic of KoreaElectronic Materials Research Center, Korea Institute of Science and Technology , Seoul 02792, Republic of KoreaRecently, to improve the performance of an integrated metal-oxide-semiconductor (MOS) device, an attempt has been made in the industry to replace the amorphous oxide with a crystalline oxide. However, various characteristics caused by the difference between amorphous and crystalline oxide in the MOS structure have not been systematically investigated. Therefore, we demonstrate the difference in atomic interface structures, electronic structures, and tunneling properties concerning varied oxide phases in a representative system, Si/SiO _2 /Si structures, with sub-3 nm-thick silica from first-principles. We investigate two oxide phases of amorphous ( a -) and crystalline ( c -) SiO _2 with and without H passivation at the interface. Si/ a -SiO _2 exhibits a smooth interface layer, whereas Si/ c -SiO _2 exhibits an abrupt interface layer, resulting in the thicker interface layer of Si/ a -SiO _2 than Si/ c -SiO _2 . Thus for a given total silica thickness, the adequate tunneling-blocking thickness, where all the Si atoms form four Si–O bonds, is thinner in a -SiO _2 than c -SiO _2 , originating more tunneling current through a -SiO _2 than c -SiO _2 . However, the effects of dangling bonds at Si/ c -SiO _2 rather than Si/ a -SiO _2 on tunneling currents are crucial, particularly in valence bands. Furthermore, when the dangling bonds are excluded by H atoms at Si/ c -SiO _2 , the tunneling current dramatically reduces, whereas the H-passivation effect on the tunneling blocking at Si/ a -SiO _2 is insignificant. Our study contributes systematic knowledge regarding oxide phases and interfaces to promote for high performance of MOS devices.https://doi.org/10.1088/2053-1591/ac639fSi/SiO2/Si structuresinterface structuresbandgaps and band offsetsleakage-tunneling currentsMOS structuresinterface engineering |
| spellingShingle | Eunjung Ko Jung-Hae Choi Comparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structures Materials Research Express Si/SiO2/Si structures interface structures bandgaps and band offsets leakage-tunneling currents MOS structures interface engineering |
| title | Comparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structures |
| title_full | Comparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structures |
| title_fullStr | Comparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structures |
| title_full_unstemmed | Comparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structures |
| title_short | Comparison of interfaces, band alignments, and tunneling currents between crystalline and amorphous silica in Si/SiO2/Si structures |
| title_sort | comparison of interfaces band alignments and tunneling currents between crystalline and amorphous silica in si sio2 si structures |
| topic | Si/SiO2/Si structures interface structures bandgaps and band offsets leakage-tunneling currents MOS structures interface engineering |
| url | https://doi.org/10.1088/2053-1591/ac639f |
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