Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structures
The alleviation effect on the Schottky barrier height (SBH) (ΦB) using ultrathin titanium dioxide and hafnium dioxide dielectrics in a single layer and a bilayer stack was demonstrated. ΦB in the Pt/n-Si contact was reduced from 0.53 to −0.058, 0.3, and −0.12 eV using 3 nm TiO2, 1 nm HfO2, and high-...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2022-07-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/5.0095003 |
| _version_ | 1811320394052796416 |
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| author | C. P. Harisha M.-H. Liao C.-C. Kei S. Joshi |
| author_facet | C. P. Harisha M.-H. Liao C.-C. Kei S. Joshi |
| author_sort | C. P. Harisha |
| collection | DOAJ |
| description | The alleviation effect on the Schottky barrier height (SBH) (ΦB) using ultrathin titanium dioxide and hafnium dioxide dielectrics in a single layer and a bilayer stack was demonstrated. ΦB in the Pt/n-Si contact was reduced from 0.53 to −0.058, 0.3, and −0.12 eV using 3 nm TiO2, 1 nm HfO2, and high-k/high-k bilayer insertion, respectively. A maximum of 122% reduction in ΦB was obtained using bilayer dielectric insertion, which is the highest ever reduction reported so far in a Schottky diode. This was achieved by effectively passivating the semiconductor surface states by HF cleaning followed by inserting an ultrathin film produced from the novel Atomic Layer Deposition (ALD) technique. The Gaussian distribution (GD) of barrier heights all over the interface has been investigated for both Metal–Semiconductor (M–S) and Metal–Insulator–Semiconductor (M–I–S) contacts. The nonlinear behavior in a conventional Richardson plot was observed with lower values of the Richardson constant (A*). We have reported the surface inhomogeneity in both M–S and M–I–S contacts through temperature dependency of diode characteristics. The standard deviation (σ) as evidence for the Gaussian distribution of barrier heights was determined using the ln(Is/T2) vs q/2kT plot. The results were validated by a modified Richardson plot where the values of A* obtained were found to be in close agreement with the known values. As the ALD technique is known for conformity and uniformity of thin films, the dielectric insertion has proved effective in mitigating the SBH. However, the inhomogeneity in both M–S and M–I–S points to the role of dipole formation at the interface. |
| first_indexed | 2024-04-13T12:57:55Z |
| format | Article |
| id | doaj.art-c14b08e4e861427799f9773a32479afb |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-04-13T12:57:55Z |
| publishDate | 2022-07-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-c14b08e4e861427799f9773a32479afb2022-12-22T02:45:59ZengAIP Publishing LLCAIP Advances2158-32262022-07-01127075117075117-810.1063/5.0095003Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structuresC. P. Harisha0M.-H. Liao1C.-C. Kei2S. Joshi3Department of Mechanical Engineering, National Taiwan University, Taipei 10617, TaiwanDepartment of Mechanical Engineering, National Taiwan University, Taipei 10617, TaiwanTaiwan Instrument Research Institute, National Applied Research Laboratories, Hsinchu 30076, TaiwanCentre for Nano-Technology, Department of Mechanical Engineering, The National Institute of Engineering, Mysuru 570008, IndiaThe alleviation effect on the Schottky barrier height (SBH) (ΦB) using ultrathin titanium dioxide and hafnium dioxide dielectrics in a single layer and a bilayer stack was demonstrated. ΦB in the Pt/n-Si contact was reduced from 0.53 to −0.058, 0.3, and −0.12 eV using 3 nm TiO2, 1 nm HfO2, and high-k/high-k bilayer insertion, respectively. A maximum of 122% reduction in ΦB was obtained using bilayer dielectric insertion, which is the highest ever reduction reported so far in a Schottky diode. This was achieved by effectively passivating the semiconductor surface states by HF cleaning followed by inserting an ultrathin film produced from the novel Atomic Layer Deposition (ALD) technique. The Gaussian distribution (GD) of barrier heights all over the interface has been investigated for both Metal–Semiconductor (M–S) and Metal–Insulator–Semiconductor (M–I–S) contacts. The nonlinear behavior in a conventional Richardson plot was observed with lower values of the Richardson constant (A*). We have reported the surface inhomogeneity in both M–S and M–I–S contacts through temperature dependency of diode characteristics. The standard deviation (σ) as evidence for the Gaussian distribution of barrier heights was determined using the ln(Is/T2) vs q/2kT plot. The results were validated by a modified Richardson plot where the values of A* obtained were found to be in close agreement with the known values. As the ALD technique is known for conformity and uniformity of thin films, the dielectric insertion has proved effective in mitigating the SBH. However, the inhomogeneity in both M–S and M–I–S points to the role of dipole formation at the interface.http://dx.doi.org/10.1063/5.0095003 |
| spellingShingle | C. P. Harisha M.-H. Liao C.-C. Kei S. Joshi Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structures AIP Advances |
| title | Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structures |
| title_full | Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structures |
| title_fullStr | Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structures |
| title_full_unstemmed | Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structures |
| title_short | Negative Schottky barrier height and surface inhomogeneity in n-silicon M–I–S structures |
| title_sort | negative schottky barrier height and surface inhomogeneity in n silicon m i s structures |
| url | http://dx.doi.org/10.1063/5.0095003 |
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