High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition Method
Al2O3, as one of the gate dielectric materials for thin film transistors (TFTs), has been extensively investigated because of its large bandgap, high breakdown field, and good thermal stability. However, the further development of Al2O3 thin films is limited by the presence of defects such as oxygen...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IEEE
2024-01-01
|
| Series: | IEEE Journal of the Electron Devices Society |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/10398479/ |
| _version_ | 1797296342850076672 |
|---|---|
| author | Pingping Li Jun Yang Xingwei Ding Xifeng Li Jianhua Zhang |
| author_facet | Pingping Li Jun Yang Xingwei Ding Xifeng Li Jianhua Zhang |
| author_sort | Pingping Li |
| collection | DOAJ |
| description | Al2O3, as one of the gate dielectric materials for thin film transistors (TFTs), has been extensively investigated because of its large bandgap, high breakdown field, and good thermal stability. However, the further development of Al2O3 thin films is limited by the presence of defects such as oxygen vacancies, self-interstitial atoms, or impurity elements. To overcome this obstacle, we have developed a novel method for fabricating Al2O3 thin films by using the atomic layer deposition (ALD) technique. This method replaces the conventional Trimethylaluminium (TMA)/H2O cycles with TMA/TMA/H2O/H2O cycles (referred to as ‘double cycles’), to deposit the Al2O3. The 5-nm ultrathin Al2O3 film showed a high areal capacitance of 660 nF/cm2 at 20 Hz, and a relatively low current density of 10−8 A/cm2 at 1 MV/cm. InGaZnO (IGZO) TFTs with ultrathin Al2O3 gate dielectric grown by double cycles exhibited outstanding performances, such as a near theoretical limit subthreshold swing (SS) of 70 mV/decade, a higher on/off current ratio <inline-formula> <tex-math notation="LaTeX">$(I_{\mathrm{ on}} / I_{\mathrm{ off}}$ </tex-math></inline-formula>) of 106, an increased field-effect mobility (<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>) of 6.5 cm2/Vs, a lower threshold voltage <inline-formula> <tex-math notation="LaTeX">$(V_{\mathrm{ th}})$ </tex-math></inline-formula> of 0.2 V, and a low operating voltage of 3 V. These results are superior to the IGZO TFTs with Al2O3 dielectrics deposited using the single TMA/H2O cycle. Therefore, the implementation of ‘double cycles’ in the fabrication of dielectrics through ALD demonstrates considerable potential for future application in low-power electronic devices. |
| first_indexed | 2024-03-07T22:03:15Z |
| format | Article |
| id | doaj.art-7028297eb52d47229cd8ede1cc938862 |
| institution | Directory Open Access Journal |
| issn | 2168-6734 |
| language | English |
| last_indexed | 2024-03-07T22:03:15Z |
| publishDate | 2024-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Journal of the Electron Devices Society |
| spelling | doaj.art-7028297eb52d47229cd8ede1cc9388622024-02-24T00:00:13ZengIEEEIEEE Journal of the Electron Devices Society2168-67342024-01-011212112610.1109/JEDS.2024.335334010398479High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition MethodPingping Li0Jun Yang1Xingwei Ding2https://orcid.org/0000-0002-9002-5185Xifeng Li3https://orcid.org/0000-0003-0508-869XJianhua Zhang4https://orcid.org/0000-0002-5594-5410Key Laboratory of Advanced Display and System Application, Ministry of Education, Shanghai University, Shanghai, ChinaInstitute for Metallic Materials, Leibniz Institute for Solid State and Materials Research, Dresden, GermanyKey Laboratory of Advanced Display and System Application, Ministry of Education, Shanghai University, Shanghai, ChinaKey Laboratory of Advanced Display and System Application, Ministry of Education, Shanghai University, Shanghai, ChinaKey Laboratory of Advanced Display and System Application, Ministry of Education, Shanghai University, Shanghai, ChinaAl2O3, as one of the gate dielectric materials for thin film transistors (TFTs), has been extensively investigated because of its large bandgap, high breakdown field, and good thermal stability. However, the further development of Al2O3 thin films is limited by the presence of defects such as oxygen vacancies, self-interstitial atoms, or impurity elements. To overcome this obstacle, we have developed a novel method for fabricating Al2O3 thin films by using the atomic layer deposition (ALD) technique. This method replaces the conventional Trimethylaluminium (TMA)/H2O cycles with TMA/TMA/H2O/H2O cycles (referred to as ‘double cycles’), to deposit the Al2O3. The 5-nm ultrathin Al2O3 film showed a high areal capacitance of 660 nF/cm2 at 20 Hz, and a relatively low current density of 10−8 A/cm2 at 1 MV/cm. InGaZnO (IGZO) TFTs with ultrathin Al2O3 gate dielectric grown by double cycles exhibited outstanding performances, such as a near theoretical limit subthreshold swing (SS) of 70 mV/decade, a higher on/off current ratio <inline-formula> <tex-math notation="LaTeX">$(I_{\mathrm{ on}} / I_{\mathrm{ off}}$ </tex-math></inline-formula>) of 106, an increased field-effect mobility (<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>) of 6.5 cm2/Vs, a lower threshold voltage <inline-formula> <tex-math notation="LaTeX">$(V_{\mathrm{ th}})$ </tex-math></inline-formula> of 0.2 V, and a low operating voltage of 3 V. These results are superior to the IGZO TFTs with Al2O3 dielectrics deposited using the single TMA/H2O cycle. Therefore, the implementation of ‘double cycles’ in the fabrication of dielectrics through ALD demonstrates considerable potential for future application in low-power electronic devices.https://ieeexplore.ieee.org/document/10398479/Ultrathin Al₂O₃atomic layer depositiondouble cyclesthin film transistor |
| spellingShingle | Pingping Li Jun Yang Xingwei Ding Xifeng Li Jianhua Zhang High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition Method IEEE Journal of the Electron Devices Society Ultrathin Al₂O₃ atomic layer deposition double cycles thin film transistor |
| title | High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition Method |
| title_full | High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition Method |
| title_fullStr | High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition Method |
| title_full_unstemmed | High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition Method |
| title_short | High-Performance of InGaZnO TFTs With an Ultrathin 5-nm Al₂O₃ Gate Dielectric Enabled by a Novel Atomic Layer Deposition Method |
| title_sort | high performance of ingazno tfts with an ultrathin 5 nm al x2082 o x2083 gate dielectric enabled by a novel atomic layer deposition method |
| topic | Ultrathin Al₂O₃ atomic layer deposition double cycles thin film transistor |
| url | https://ieeexplore.ieee.org/document/10398479/ |
| work_keys_str_mv | AT pingpingli highperformanceofingaznotftswithanultrathin5nmalx2082ox2083gatedielectricenabledbyanovelatomiclayerdepositionmethod AT junyang highperformanceofingaznotftswithanultrathin5nmalx2082ox2083gatedielectricenabledbyanovelatomiclayerdepositionmethod AT xingweiding highperformanceofingaznotftswithanultrathin5nmalx2082ox2083gatedielectricenabledbyanovelatomiclayerdepositionmethod AT xifengli highperformanceofingaznotftswithanultrathin5nmalx2082ox2083gatedielectricenabledbyanovelatomiclayerdepositionmethod AT jianhuazhang highperformanceofingaznotftswithanultrathin5nmalx2082ox2083gatedielectricenabledbyanovelatomiclayerdepositionmethod |