Flexible electronics has gained interest in recent times, with some studies focused on the fabrication of flexible magnetoresistive sensors via direct growth of thin films on flexible polymeric substrates. As it is well known that the properties such as coercivity, squareness or abruptness of switching, and magnetoresistance are dependent on the intrinsic strain of the device. The direct growth of thin film on flexible substrates could limit the performance of such devices because the strain cannot be engineered to the desired properties.
We descriped here a novel approach to fabricating flexible magnetoresistive device through the etching of (eg. magnetoresistive) devices off the underlying substrate to enable the relaxation of the intrinsic stress in the thin film structure of the devices, thus imparting strain to the devices. In this way, the device properties can be engineered to the desired level. This technique allows transfer-and-attach devices onto a new substrate, such as flexible polymeric substrate. The second substrate could also be contoured to impart further amounts of strain to the devices along specific directions, as desired.
The technology comprises a method of fabricating thin film magnetoresistive devices with specified amounts of intrinsic thin film stress, then etching the magnetoresistive devices off their underlying substrate such that the desired intrinsic stress relaxation is achieved, thereby modifying the device properties desirably, and transferring as well as attaching the devices onto a new substrate, such as, but not limited to, a flexible polymeric substrate. The second substrate could also be contoured to impart further amounts of strain to the devices along specific directions, as desired.
The invention is important in fields such as flexible magnetic data storage systems for wearable electronics, magnetic sensing devices or lab‐on‐chips for biomedical applications, as well as strain gauge applications, as it provides a unique combination of high quality, flexible magnetoresistive devices on one hand, and strain‐tunable device properties on the other.
According to market research report titled “Flexible Electronics Market by Components (Display, Battery, Sensor, Photovoltaic, Memory), Circuit Structure (Single-Sided, Double-Sided, Rigid) Application (Consumer Electronics, Healthcare, Automotive, Energy and Power), & by Geography - Analysis & Forecast to 2014 - 2020”, published by MarketsandMarkets, the total market is expected to reach $13.23 Billion by 2020.
- High quality, flexible magnetoresistive devices
- The strain and/or magnetic properties of the device can be engineered to the desired level and this can be further modulated when the underlying substrate can also be contoured to impart further amounts of strain to the devices along specific directions
- This method allows devices to integrate with different underlying substrates such as polymeric substrates