Improvement of the multilayer morphology (alumina/Cu/YIG/Cu) to characterize YIG thin film

Abstract

International audienceThe aim of our study is to characterize yttrium iron garnet (YIG) thin film for its applications in the microwaves and magnetooptical domains. For this purpose, we have manufactured a microinductor by deposition of YIG film between two copper layers on an alumina substrate. Multilayers have been deposited by radio-frequency magnetron sputtering technique. Thin films of YIG are amorphous after deposition; a post-thermal annealing at 740 8C for 2 h is necessary to obtain satisfactory magnetic properties. In this work, we have studied the effects of different parameters concerning the substrate surface state, deposition and post-thermal treatment of YIG and copper thin films on their structure and morphological properties. We have come against several mechanical and electrical problems: crack formation, detachment of YIG or Cu films from the substrate, deterioration of Cu films, open or short circuits. The roughness of alumina substrate and the annealing mode play an important role on the quality of themicroinductor prototype. After several tests by varying different parameters, we have established a protocol permitting to manufacture a prototype of good quality. This prototype is characterized using: profilometry, scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and a precision LCR meter

Determination of Initial Magnetic Permeability of YIG Thin Films Using the Current Sheet Method

“…The SEM images are analyzed to characterize the morphological properties of YIG and Cu films. XRD patterns and magnetic hysteresis loops obtained by VSM prove that YIG film is well-crystallized magnetic material [9].…”

“…Magnetic and dielectric characterization at low and high frequency ranges are essential for the development of these previous applications. A new technique of inductive measure, for the characterization of non conducting magnetic thin films, has been conceived and developed in our Laboratory [7][8][9]. The originality of this technique resides in the fact that the substrate has been put outside the measuring circuit.…”

“…Thin film of YIG is deposited on an alumina substrate between two layers of copper by radio frequency magnetron sputtering technique. After deposition, the YIG film does not have magnetic properties, a supply of additional energy is necessary to be crystallized [9]; this supply of energy is obtained by a thermal annealing in vacuum for 2 hours at 740 °C. According to the results of the different tests considering the geometrical, morphological and magnetic properties, we have established a protocol permitting to manufacture a prototype of good qualities.…”

Fabrication and characterization of micro-inductors deposited on magnetic thin and thick layers

“…Morphological, crystallographic and magnetic characterizations of the obtained YIG films are then done. The thickness of the layer is measured by using a profilometer while images obtained by a Scanning Electron Microscope (SEM) permit to check the quality of the films surface [20]. The crystallographic characterization of YIG layers is obtained by X-ray diffraction (XRD).…”

“…The final thickness could be controlled with a high accuracy (a few microns). The substrate roughness has an influence on the electromagnetic properties, but also on the mechanical properties of the components [20]. The effect of roughness on performance of biosensors was fully addressed for plane biosensors and gratings [23].…”