Search

EP-3696869-B1 - NANO-SCALE SINGLE CRYSTAL THIN FILM

EP3696869B1EP 3696869 B1EP3696869 B1EP 3696869B1EP-3696869-B1

Inventors

  • HU, HUI
  • ZHU, Houbin
  • HU, WEN
  • LUO, Juting
  • ZHANG, Xiuquan
  • LI, ZHENYU
  • LI, YANGYANG

Dates

Publication Date
20260506
Application Date
20180621

Claims (9)

  1. A nano-scale single crystal thin film (10), comprising: a nano-scale single crystal thin film layer (100), an isolation layer (400), a substrate layer (200), and a first transition layer (310) and a second transition layer (320), wherein the first transition layer (310) is located between the nano-scale single crystal thin film layer (100) and the isolation layer and the second transition layer (320) is located between the isolation layer (400) and the substrate layer (200), wherein the first transition layer (310) is amorphous, wherein the first transition layer (310) contains a certain concentration of element hydrogen, H, characterised in that the concentration of the element H in the first transition layer (310) is in the range of 1x10 19 atoms/cm 3 to 1x10 22 atoms/cm 3 , wherein the element H is derived from water molecules adsorbed on a surface of a target thin film wafer and/or a substrate wafer after a plasma treatment of the surface.
  2. The nano-scale single crystal thin film (10) according to claim 1, wherein the material that forms the nano-scale single crystal thin film layer (100) is lithium niobate, lithium tantalate, or quartz, and the nano-scale single crystal thin film layer (100) has a thickness in the range of 10 nm to 2,000 nm.
  3. The nano-scale single crystal thin film (10) according to claim 1, wherein the material that forms the substrate layer (200) is lithium niobate, lithium tantalate, silicon, quartz, sapphire, or silicon carbide, and the substrate layer (200) has a thickness in a range from 0.1 mm to 1 mm.
  4. The nano-scale single crystal thin film (10) according to claim 1, wherein the isolation layer (400) is a silicon dioxide layer, and the isolation layer (400) has a thickness in the range of 0.05 µm to 4 µm, the first transition layer I (310) has a thickness in the range of 2 nm to 10 nm, and the second transition layer (320) has a thickness in the range of 0.5 nm to 15 nm.
  5. The nano-scale single crystal thin film (10) according to claim 1, wherein the first transitior layer (310) has a thickness that is different from the thickness of the second transition layer (320).
  6. The nano-scale single crystal thin film (10) according to claims 1, 2, 3, or 4, wherein the material that forms the nano-scale single crystal thin film layer (100) is the same as the material of the substrate layer (200).
  7. The nano-scale single crystal thin film (10) according to claims 1, 2, 3, or 4, wherein the material that forms the nano-scale single crystal thin film layer (100) is different from the material of the substrate layer (200).
  8. The nano-scale single crystal thin film (10) according to claim 1, wherein, in the first transitior layer (310), in a direction from the nano-scale single crystal thin film layer (100) toward the isolation layer (400), the content of an element from the nano-scale single crystal thin film layer (100) gradually decreases and the content of an element from the isolation layer (400) gradually increases; and in the second transitior layer (320), in the direction from the isolation layer (400) toward the substrate layer (200), the content of an element from the isolation layer (400) gradually decreases and the content of an element from the substrate layer (200) gradually increases.
  9. The nano-scale single crystal thin film (10) according to claim 1, wherein the element H in the first transition layer (310) has a maximum concentration at a certain position and the concentration of the element H in the first transition layer (310) gradually decreases from the position with maximum concentration toward the isolation layer (400) and the nano-scale single crystal thin film layer (100).

Description

FIELD OF TECHNOLOGY The disclosure relates to a nano-scale single crystal thin film and in particular to a nano-scale single crystal thin film comprising a thin film layer with a thickness in the range of 10 nm to 2,000 nm. BACKGROUND Oxide single crystal thin films, such as lithium tantalate single crystal thin films and lithium niobate single crystal thin films, due to their large electromechanical coupling coefficients, are widely used as piezoelectric materials in surface acoustic wave (SAW) elements, and they are widely used in optical signal processing, information storage, electronic devices, and similar areas. These oxide single crystal thin films can be used as basic materials to prepare optoelectronic devices and integrated optical circuits with the features of high frequency, high bandwidth, high integration, high capacity, and low power. As the demand for reducing the power consumption of devices, reducing the volumes of devices, and increasing the integration level of devices has become higher and higher, the thickness of wafers has become thinner and thinner. SUMMARY The invention provides a nano-scale single crystal thin film that can improve the bonding force between a single crystal thin film and a substrate as defined by claim 1. According to an embodiment of the invention, the material for forming the nano-scale single crystal thin film layer may be lithium niobate, lithium tantalate, or quartz, and the thickness of the nano-scale single crystal thin film layer may be in the range of 10 nm to 2,000 nm. According to an embodiment of the invention, the material for forming the substrate layer may be lithium niobate, lithium tantalate, silicon, quartz, sapphire, or silicon carbide, and the thickness of the substrate layer may be in the range of 0.1 mm to 1 mm. According to an embodiment of the invention, the isolation layer may be a silicon dioxide layer. The thickness of the isolation layer may be in the range of 0.05 µm to 4 µm, the thickness of the first transition layer may be in the range of 2 nm to 10 nm, and the thickness of the second transition layer may be in the range of 0.5 nm to 15 nm. According to an embodiment of the invention, the first transition layer may have a thickness that is different from the thickness of the second transition layer. According to an embodiment of the invention, the material for forming the nano-scale single crystal thin film layer may be the same as the material of the substrate layer. According to an embodiment of the invention, the material for forming the nano-scale single crystal thin film layer may be different from the material of the substrate layer. According to an embodiment of the invention, in the first transition layer, in the direction from the nano-scale single crystal thin film layer to the isolation layer, the content of the element from the nano-scale single crystal thin film layer may gradually decrease, and a content of the element from the isolation layer may gradually increase. In the second transition layer, in the direction from the isolation layer to the substrate layer, a content of the element from the isolation layer may gradually decrease, and the content of the element from the substrate layer may gradually increase. According to an embodiment of the invention, the element H in the first transition layer may have a maximum concentration at a certain position, and the concentration of the element H in the first transition layer may gradually decrease from the position with maximum concentration toward the isolation layer and the nano-scale single crystal thin film layer. According to the invention, the first transition layer and the second transition layer of the nano-scale single crystal thin film can release stress, reduce defects in the single crystal thin film and the isolation layer, and improve the quality of the single crystal thin film and the isolation layer, thereby reducing transmission losses. In addition, the stress release can make the media at interfaces have more uniformity and reduce the scattering of light during a propagation process, thereby reducing the transmission losses. According to the invention, the element H in the first transition layer is beneficial for improving the bonding force of the single crystal thin film, and in the preparation of a filter device using the nano-scale single crystal thin film, the phenomenon of large-area debonding can be avoided when a cutting process is performed. Therefore, the utilization rate of the nano-scale single crystal thin film can be improved, and the yield of the filter device can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS The above description and other objects and features of the disclosure will become clearer through the following description of exemplary embodiments in conjunction with the accompanying drawings, among which: Figure 1 is a schematic diagram illustrating a nano-scale single crystal thin film according to the invention.Figure 2