Journal of Inorganic Materials >
Heteroepitaxial Diamond Nucleation and Growth on Iridium: First-principle Calculation
Received date: 2023-08-30
Revised date: 2023-11-06
Online published: 2024-04-25
Supported by
National Key R&D Program of China(2020YFA0709700)
National Key R&D Program of China(2016YFE0201600)
National Natural Science Foundation of China(52072087)
Guangdong Key Research and Development Program(2020B010169002)
Heilongjiang Natural Science Foundation(YQ2020E008)
The Fundamental Research Funds for the Central Universities(HIT.OCEF.2022048)
Heteroepitaxy provides an effective path for the synthesis of diamond wafers. After more than 20 years of development, the diamond nucleation and growth technology on iridium substrates has enabled to prepare crystals with a maximum diameter of 3.5 inches, which opens a door to application diamond as ultimate semiconductor in the future chip industry. However, a series of problems that occur on heterogeneous substrates, such as surface nucleation, bias process window, and diamond epitaxial growth, need to overcome from the perspective of growth thermodynamics. In this study, aiming at the key issue how diamond can achieve epitaxial nucleation and growth in chemical vapor deposition atmosphere, a simulation study was carried out on the nucleation and growth process of diamond at the atomic scale based on the first-principle calculation. The results show that the adsorption of C atoms on the surface of the Ir substrate is more stable than that on the bulk phase, which indicates that diamond nucleation can only occur on the substrate surface. The number of C atoms of sp3 hybridization in the amorphous hydrogenated carbon layer increases firstly and then decreases with the increase of ion kinetic energy under ion bombardment, confirming the existence of the ion kinetic energy or bias voltage window in the high-density nucleation of diamond. The interfacial binding energy is the lowest (about -0.58 eV/C) when diamond is epitaxially grown along the Ir substrate, meaning that the interface binding energy is the decisive thermodynamic factor for the epitaxial growth. In conclusion, this study clarifies the thermodynamic mechanism of single crystal diamond epitaxial growth under the bias-assisted ion bombardment, and points out a great significant guidance for the growth of diamond and other carbon based semiconductors.
Key words: diamond; heteroepitaxy; nucleation and growth; first-principle; binding energy
Weihua WANG , Leining ZHANG , Feng DING , Bing DAI , Jiecai HAN , Jiaqi ZHU , Yi JIA , Yu Yang . Heteroepitaxial Diamond Nucleation and Growth on Iridium: First-principle Calculation[J]. Journal of Inorganic Materials, 2024 , 39(4) : 416 -422 . DOI: 10.15541/jim20230392
图1 C原子在Ir衬底上的吸附模型及行为Fig. 1 Adsorption modes and behaviors of C atom on Ir substrate (a) Adsorption modes of C atom in octa-site (O), tetra-site (T) and subs-site (S) of the surface; (b) Adsorption energy when one C atom is adsorbed on different sites of Ir substrate; (c) Adsorption energy variation of C atoms adsorbed on different depths from Ir (001) surface |
表1 不同速率CH3+离子轰击表面后形成a-C:H层中C原子个数及sp3-C原子个数.Table 1 Carbon atom number and sp3-bonded carbon number in the a-C:H layer after the CH3+ ion bombardment with different rates |
Ion rate | 0.005 nm/fs | 0.011 nm/fs | 0.019 nm/fs | 0.025 nm/fs | 0.030 nm/fs | 0.035 nm/fs | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Number Step | C atom | sp3-C atom | C atom | sp3-C atom | C atom | sp3-C atom | C atom | sp3-C atom | C atom | sp3-C atom | C atom | sp3-C atom |
2500 | 4 | 0 | 4 | 0 | 6 | 0 | 6 | 0 | 6 | 0 | 6 | 0 |
5000 | 9 | 0 | 7 | 1 | 9 | 0 | 11 | 0 | 11 | 0 | 11 | 0 |
7500 | 6 | 0 | 13 | 1 | 15 | 0 | 15 | 0 | 17 | 0 | 17 | 1 |
10000 | - | 16 | 3 | 21 | 1 | 17 | 2 | 20 | 2 | 23 | 1 | |
12500 | 21 | 4 | 22 | 1 | 18 | 2 | 23 | 0 | 26 | 1 | ||
15000 | 17 | 5 | - | - | - | - | - |
图2 不同速率CH3+离子轰击表面后所有C原子的成键类型Fig. 2 Bonding types of C atoms after the CH3+ ion bombardment with different ion rates (a) 0.005 nm/fs; (b) 0.011 nm/fs; (c) 0.019 nm/fs; (d) 0.025 nm/fs; (e) 0.030 nm/fs; (f) 0.035 nm/fs Atoms with the atomic size from large to small representing Ir, C and H, and C atom with the color from blue to red representing the bonding number of C atom from 0 to 4. Colorful figures are available on website |
图3 金刚石(001)团簇与Ir(001)衬底夹角θ=0°、10°、25°和45°时的结构Fig. 3 Structure of cluster model of diamond (001) and Ir (001) surface as a function of the alignment angle θ=0°, 10°, 25° and 45° When θ are 0° and 45°, the in-plane orientation relationships are diamond(001)[010]//Ir(001)[010] and diamond(001)[110]//Ir(001)[010], respectively |
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