Abstract:
A pressure-sensing device (10) and a process for fabricating it is disclosed. In a preferred embodiment, a sacrificial oxide layer (11 ) is first formed onto a silicon substrate (30). A bottom polymer film (14) is then formed on oxide layer (11 ). Conductive elements including electrodes (12a, 12b) and/or contact pads (18a, 18b) are formed on the bottom polymer film (14). A graphene sheet (20) is deposited to electrically connect the electrodes (12a, 12b). A top polymer film (16) is then laid on top so that the conductive elements (12, 18) and graphene (20) are sandwiched and encapsulated in between the top and bottom polymer layers (14, 16) chosen from polyimide or poly dimethylsiloxane (PDMS). Openings (19a, 19b) on top polymer layer (16) may optionally be provided to allow for interconnection of the contact pads (18a, 18b). The sacrificial oxide (11 ) is then etched to release the completed device (10) from the substrate (30) which may be reused.
Abstract:
Described herein is a metal electrode (100) having at least one high aspect ratio structure. The metal electrode (100) comprises a silicon layer (101) having the high aspect ratio structure, an oxide layer (102) on top of the silicon layer (101), an adhesive layer (103) on top of the oxide layer (102), and a metal layer (104) on top of the adhesive layer (103). The thickness of the metal layer (104) is at least 15 times lesser than the height of the high aspect ratio structure. Due to this particular feature, the metal layer (104) is deposited on top of the adhesive layer (103) in a self-aligned manner, taking the shape of the high aspect ratio structure, and disconnected at the wall of the high aspect ratio structure. Further, the metal electrode (100) can be modified accordingly to suit different applications. Also described herein is a method for fabricating the aforementioned metal electrode (100).
Abstract:
The present invention relates to an extended gate field effect transistor (EGFET) with a phosphate selective alloy membrane (80) that has a high sensitivity towards phosphate ions in a solution and improves corrosion rate. The phosphate selective alloy membrane (80) can be made of a binary, ternary, quaternary, or quinary alloy. The EGFET also includes feature such as an extended gate metallisation layer (60) made of a metallic or a non-metallic conductor, which enables the phosphate selective alloy membrane (80) to be separated from the FET wafer of the EGFET. A method for fabricating said EGFET is also disclosed in the present invention. In order to ensure the reliability and accuracy of the EGFET phosphate sensor device when sensing phosphate ions in the solution, and preventing any chemical components from leaching away and further damaging the sensor device, the method emphasises on the steps of depositing the extended gate metallisation layer (60) on the gate terminal (50); depositing the phosphate selective alloy membrane (80) in sensing pad area so that the phosphate selective alloy membrane (80) is in contact with the solution; and creating an epoxy dam (90) for controlling the exposure of the phosphate selective alloy membrane (80) to target analyte in the solution.