Crystallization kinetics and role of stress in Al induced layer exchange crystallization process of amorphous SiGe thin film on glass

Sain, Twisha; Singh, Ch. Kishan; Ilango, S.; Mathews, Tom

doi:10.1063/1.5115539

Cited by 12 publications

(7 citation statements)

References 54 publications

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“…This aspect also depends on the type and even the thickness of the substrate [79,80]. This is because the stress applied to the metal and semiconductor layers during LE considerably affect growth morphology [81][82][83][84]. The islands can be removed by peeling off with tape [85] or using dry [86] and wet etching techniques [74,87].…”

Section: Characteristics Of Layer-exchanged Thin Films 231 Film Shapementioning

confidence: 99%

Metal-induced layer exchange of group IV materials

Toko

Suemasu

2020

J. Phys. D: Appl. Phys.

108

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Layer exchange (LE) is an interesting phenomenon in which metal and semiconductor layers exchange during heat treatment. A great deal of effort has been put into research on the mechanism and applications of LE, which has allowed various group IV materials (Si, SiGe, Ge, GeSn and C) to form on arbitrary substrates using appropriate metal catalysts. Depending on the LE material combination and growth conditions, the resulting semiconductor layer exhibits various features: low-temperature crystallization (80 °C–500 °C), grain size control (nm to mm orders), crystal orientation control to (100) or (111) and high impurity doping (>1020 cm−3). These features are useful for improving the performance, productivity and versatility of various devices, such as solar cells, transistors, thermoelectric generators and rechargeable batteries. We briefly review the findings and achievements from over 20 years of LE studies, including recent progress on device applications.

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Section: Characteristics Of Layer-exchanged Thin Films 231 Film Shapementioning

confidence: 99%

Metal-induced layer exchange of group IV materials

Toko

Suemasu

2020

J. Phys. D: Appl. Phys.

108

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“…The values of macrostresses (σ) were calculated by Hooke's law using the obtained values of the crystal lattice constants of aluminum and silicon as well as the values of the Young's modulus typical for polycrystalline aluminum and silicon (see Table 3). The obtained values of the macrostresses in the silicon and aluminum layers in terms of their order of magnitude are characteristic for heteroepitaxy in thin film systems [43], and they were observed in Al/Si thin films earlier [44,45]. It is worth noting that it was impossible to estimate microstrain in the (Al/Si) n films after heating due to a high degree of defects.…”

Section: Tem and Xrdmentioning

confidence: 79%

Thermokinetic Study of Aluminum-Induced Crystallization of a-Si: The Effect of Al Layer Thickness

Zharkov,

Yumashev,

Moiseenko

et al. 2023

Nanomaterials

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The effect of the aluminum layer on the kinetics and mechanism of aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) in (Al/a-Si)n multilayered films was studied using a complex of in situ methods (simultaneous thermal analysis, transmission electron microscopy, electron diffraction, and four-point probe resistance measurement) and ex situ methods (X-ray diffraction and optical microscopy). An increase in the thickness of the aluminum layer from 10 to 80 nm was found to result in a decrease in the value of the apparent activation energy Ea of silicon crystallization from 137 to 117 kJ/mol (as estimated by the Kissinger method) as well as an increase in the crystallization heat from 12.3 to 16.0 kJ/(mol Si). The detailed kinetic analysis showed that the change in the thickness of an individual Al layer could lead to a qualitative change in the mechanism of aluminum-induced silicon crystallization: with the thickness of Al ≤ 20 nm. The process followed two parallel routes described by the n-th order reaction equation with autocatalysis (Cn-X) and the Avrami–Erofeev equation (An): with an increase in the thickness of Al ≥ 40 nm, the process occurred in two consecutive steps. The first one can be described by the n-th order reaction equation with autocatalysis (Cn-X), and the second one can be described by the n-th order reaction equation (Fn). The change in the mechanism of amorphous silicon crystallization was assumed to be due to the influence of the degree of Al defects at the initial state on the kinetics of the crystallization process.

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“…Furthermore, there is an obvious red shift in peaks 1, 2, and 3 with increasing annealing temperature, which confirms the presence of tensile stress in the Ge-Cu-Te thin films; such tensile stress may originate from the thickness changes during the thermally-induced crystallization. [42][43][44][45][46][47] The surface oxidation and chemical bonding states of the asdeposited and annealed Ge-Cu-Te thin films are characterized by the XPS data obtained before and after Ar + ion sputtering (Fig. 6).…”

Section: Resultsmentioning

confidence: 99%

Elemental Redistribution During the Crystallization of Ge–Cu–Te Thin Films for Phase-Change Memory

Wang¹,

Chen²

2023

ECS J. Solid State Sci. Technol.

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Herein, a GeCu2Te2 alloy is proposed as a phase-change material for application in nonvolatile phase-change random access memory (PRAM). The crystallization kinetics and microchemical changes during phase transformation are investigated, and their correlation with the electrical behaviors of the GeCu2Te2 thin films are examined. The key findings are as follows: (ⅰ) the GeCu2Te2 alloy shows a higher crystallization temperature (~185°C) than the classic Ge2Sb2Te5 (GST) thin films, thus demonstrating superior thermal stability; (ⅱ) the crystallization kinetics demonstrate a decreasing in the Avrami exponent n from 4, which is related to the growth-dominated crystallization process evidenced by the micromorphology; (ⅲ) a massive redistribution of the chemical elements along the depth of the thin films during crystallization is considered to be driven by selective surface oxidation at amorphous state, and stress buildup during crystallization. In addition, the crystallization-induced stress is determined as ~168 MPa by utilizing the wafer curvature and X-ray diffraction methods for the GeCu2Te2 thin films. Finally, the lower threshold switching voltage ~1.72 V for amorphous GeCu2Te2 thin films is beneficial for reducing the SET operating power consumption. The authors believe that these results are valuable for the optimal phase change material design.

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Crystallization kinetics and role of stress in Al induced layer exchange crystallization process of amorphous SiGe thin film on glass

Cited by 12 publications

References 54 publications

Metal-induced layer exchange of group IV materials

Metal-induced layer exchange of group IV materials

Thermokinetic Study of Aluminum-Induced Crystallization of a-Si: The Effect of Al Layer Thickness

Elemental Redistribution During the Crystallization of Ge–Cu–Te Thin Films for Phase-Change Memory

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