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Structural and Insulating Behaviour of High-Permittivity Binary Oxide Thin Films for Silicon Carbide and Gallium Nitride Electronic Devices. MATERIALS 2022; 15:ma15030830. [PMID: 35160775 PMCID: PMC8836874 DOI: 10.3390/ma15030830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/04/2023]
Abstract
High-κ dielectrics are insulating materials with higher permittivity than silicon dioxide. These materials have already found application in microelectronics, mainly as gate insulators or passivating layers for silicon (Si) technology. However, since the last decade, the post-Si era began with the pervasive introduction of wide band gap (WBG) semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), which opened new perspectives for high-κ materials in these emerging technologies. In this context, aluminium and hafnium oxides (i.e., Al2O3, HfO2) and some rare earth oxides (e.g., CeO2, Gd2O3, Sc2O3) are promising high-κ binary oxides that can find application as gate dielectric layers in the next generation of high-power and high-frequency transistors based on SiC and GaN. This review paper gives a general overview of high-permittivity binary oxides thin films for post-Si electronic devices. In particular, focus is placed on high-κ binary oxides grown by atomic layer deposition on WBG semiconductors (silicon carbide and gallium nitride), as either amorphous or crystalline films. The impacts of deposition modes and pre- or postdeposition treatments are both discussed. Moreover, the dielectric behaviour of these films is also presented, and some examples of high-κ binary oxides applied to SiC and GaN transistors are reported. The potential advantages and the current limitations of these technologies are highlighted.
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Lee SM, Yum JH, Yoon S, Larsen ES, Lee WC, Kim SK, Shervin S, Wang W, Ryou JH, Bielawski CW, Oh J. Atomic-Layer Deposition of Single-Crystalline BeO Epitaxially Grown on GaN Substrates. ACS APPLIED MATERIALS & INTERFACES 2017; 9:41973-41979. [PMID: 29148718 DOI: 10.1021/acsami.7b13487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have grown a single-crystal beryllium oxide (BeO) thin film on a gallium nitride (GaN) substrate by atomic-layer deposition (ALD) for the first time. BeO has a higher thermal conductivity, bandgap energy, and dielectric constant than SiO2. As an electrical insulator, diamond is the only material on earth whose thermal conductivity exceeds that of BeO. Despite these advantages, there is no chemical-vapor-deposition technique for BeO-thin-film deposition, and thus, it is not used in nanoscale-semiconductor-device processing. In this study, the BeO thin films grown on a GaN substrate with a single crystal showed excellent interface and thermal stability. Transmission electron microscopy showed clear diffraction patterns, and the Raman shifts associated with soft phonon modes verified the high thermal conductivity. The X-ray scan confirmed the out-of-plane single-crystal growth direction and the in-plane, 6-fold, symmetrical wurtzite structure. Single-crystalline BeO was grown on GaN despite the large lattice mismatch, which suggested a model that accommodated the strain of hexagonal-on-hexagonal epitaxy with 5/6 and 6/7 domain matching. BeO has a good dielectric constant and good thermal conductivity, bandgap energy, and single-crystal characteristics, so it is suitable for the gate dielectric of power semiconductor devices. The capacitance-voltage (C-V) results of BeO on a GaN-metal-oxide semiconductor exhibited low frequency dispersion, hysteresis, and interface-defect density.
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Affiliation(s)
- Seung Min Lee
- School of Integrated Technology, Yonsei University , Incheon 21983, Republic of Korea
- Yonsei Institute of Convergence Technology , Incheon 21983, Republic of Korea
| | - Jung Hwan Yum
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 44919, Republic of Korea
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
| | - Seonno Yoon
- School of Integrated Technology, Yonsei University , Incheon 21983, Republic of Korea
- Yonsei Institute of Convergence Technology , Incheon 21983, Republic of Korea
| | - Eric S Larsen
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 44919, Republic of Korea
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
| | - Woo Chul Lee
- Center for Electronic Materials, Korea Institute of Science and Technology (KIST) , Seoul 20792, Republic of Korea
| | - Seong Keun Kim
- Center for Electronic Materials, Korea Institute of Science and Technology (KIST) , Seoul 20792, Republic of Korea
| | - Shahab Shervin
- Department of Mechanical Engineering, University of Houston , Houston, Texas 77204-4006, United States
| | - Weijie Wang
- Department of Mechanical Engineering, University of Houston , Houston, Texas 77204-4006, United States
| | - Jae-Hyun Ryou
- Department of Mechanical Engineering, University of Houston , Houston, Texas 77204-4006, United States
- Materials Science and Engineering Program and Texas Center for Superconductivity at UH (TcSUH), University of Houston , Houston, Texas 77204, United States
| | - Christopher W Bielawski
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 44919, Republic of Korea
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
- Department of Energy Engineering, UNIST , Ulsan 44919, Republic of Korea
| | - Jungwoo Oh
- School of Integrated Technology, Yonsei University , Incheon 21983, Republic of Korea
- Yonsei Institute of Convergence Technology , Incheon 21983, Republic of Korea
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