Amorphous thin film for sensing

Abstract

An apparatus and method for low-power sensing, for example, sensing of chemical or biochemical analytes in a gas or liquid phase are disclosed. One aspect relates to the use of a thin continuous film without grain boundaries as a sensing layer in devices for sensing a predetermined analyte and to low power devices having such sensing layer. The sensing layer has a surface exposed to the analyte. The electrical impedance of the sensing layer changes upon adsorption of the predetermined analyte on the exposed surface of the sensing layer. The sensing layer may have a thickness in the range between about 1 nm and 100 nm, such as between about 1 nm and 30 nm. The sensing layer may be an amorphous layer.

What is claimed is: 
     
         1 . A low power device for sensing a predetermined analyte, the device comprising:
 a sensing layer having a surface in use exposed to the predetermined analyte, wherein the electrical impedance of the sensing layer changes upon adsorption of the predetermined analyte on the exposed surface of the sensing layer, wherein the sensing layer is an amorphous thin continuous film without grain boundaries; and   a field electrode separated from the exposed surface of the sensing layer by a gap, the field electrode configured to apply an electric field over the sensing layer, thereby electrically controlling adsorption and desorption of the predetermined analyte at the exposed surface of the sensing layer;   wherein the gap between the field electrode and the sensing layer comprises a local environment of the sensor.   
     
     
         2 . The device according to  claim 1 , wherein the sensing layer has a thickness in the range between about 1 nm and 100 nm. 
     
     
         3 . The device according to  claim 2 , wherein the sensing layer has a thickness in the range between about 1 nm and 30 nm 
     
     
         4 . The device according to  claim 1 , wherein the sensing layer is formed of one or more of the following: a polymer, an inorganic material, an oxide, a nitride, and a semiconductor, SiO 2 , Al 2 O 3 , HfO 2 , Ta 2 O 5 , ZrO 2 , titanium oxide, iron oxide, manganese oxide, chromium oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, tin oxide, molybdenum oxide, zirconium oxide, tungsten oxide, iridium oxide, an oxide of the lanthanide series, a noble metal catalyst particle, SiN, SiC, n-type or p-type doped silicon, a III-V binary, ternary and quaternary alloy, GaN, and a II-VI compound. 
     
     
         5 . The device according to  claim 1 , further comprising a first measurement electrode and a second measurement electrode which are configured to measure the electrical impedance of the sensing layer and to sense the predetermined analyte based on detecting changes of the electrical impedance. 
     
     
         6 . The device according to  claim 4 , wherein one of the first measurement electrode and the second measurement electrode is used as the field electrode. 
     
     
         7 . The device according to  claim 4 , wherein the device is a capacitor and wherein the sensing layer is an electrically insulating layer being provided between the first measurement electrode and the second measurement electrode. 
     
     
         8 . The device according to  claim 7 , further comprising a semiconductor layer in between the first measurement electrode and the sensing layer. 
     
     
         9 . The device according to  claim 1 , wherein the device is a transistor and the sensing layer is a gate dielectric layer. 
     
     
         10 . The device according to  claim 1 , wherein the device is a transistor and the sensing layer is a semiconducting channel layer. 
     
     
         11 . The device according to  claim 1 , wherein the sensing layer is located on a structured surface, the structured surface comprising nanoscopic and/or microscopic structures. 
     
     
         12 . The device according to  claim 1 , wherein the structures comprise one or more of the following: lines, dots, trenches, pores, a complex 3D structure, an open structure to allow easy molecule penetration through it, a periodic array of structures, and a sharp edge. 
     
     
         13 . A semiconductor apparatus comprising a device according to  claim 1 .