Semiconductor device-based sensors and methods associated with the same

Abstract

Semiconductor device-based chemical sensors and methods associated with the same are provided. The sensors include regions that can interact with chemical species being detected. The chemical species may, for example, be a component of a fluid (e.g., gas or liquid). The interaction between the chemical species and a region of the sensor causes a change in a measurable property (e.g., an electrical property) of the device. These changes may be related to the concentration of the chemical species in the medium being characterized.

1 . A FET-based chemical sensor designed to detect a chemical species comprising:
 a semiconductor material region;   a source electrode formed on the semiconductor material region;   a drain electrode formed on the semiconductor material region;   a gate electrode formed on the semiconductor material region; and   a sensing region, separated from the gate electrode, and capable of interacting with the chemical species to change a measurable property of the chemical sensor.   
     
     
         2 . The sensor of  claim 1 , wherein the sensing region comprises a sensing layer. 
     
     
         3 . The sensor of  claim 2 , wherein the sensing layer has a thickness of less than 500 nm. 
     
     
         4 . The sensor of  claim 2 , wherein the sensing region further comprises a surface region of the semiconductor material region positioned under the sensing layer. 
     
     
         5 . The sensor of  claim 1 , wherein the sensing region comprises an exposed surface region of the semiconductor material region. 
     
     
         6 . The sensor of  claim 1 , wherein the sensing region is formed between the source electrode and the drain electrode. 
     
     
         7 . The sensor of  claim 1 , wherein a ratio of sensing electrode surface area to total channel surface area is greater than 0.35. 
     
     
         8 . The sensor of  claim 1 , wherein the sensing region comprises a sensing electrode. 
     
     
         9 . The sensor of  claim 8 , wherein a separate voltage may be applied to each of the source, drain, gate and sensing electrodes. 
     
     
         10 . The sensor of  claim 1 , wherein respective electrical contacts to each of the source, drain, gate and sensing electrodes are formed on a backside of the sensor. 
     
     
         11 . The sensor of  claim 1 , wherein the sensor is substantially free of electrical contacts on a frontside of the sensor in areas separate from the sensing region. 
     
     
         12 . The sensor of  claim 1 , wherein the semiconductor region comprises a gallium nitride material layer. 
     
     
         13 . The sensor of  claim 12 , wherein the sensing region is formed, at least in part, in the gallium nitride material layer. 
     
     
         14 . The sensor of  claim 12 , wherein the gallium nitride material layer has a crack level of less than about 0.005 micron/micron 2 . 
     
     
         15 . The sensor of  claim 1 , further comprising a substrate. 
     
     
         16 . The sensor of  claim 15 , wherein the substrate is a silicon substrate. 
     
     
         17 - 28 . (canceled) 
     
     
         29 . A semiconductor device-based chemical sensor comprising:
 a semiconductor material region;   a first electrode formed on the semiconductor material region;   a second electrode formed on the semiconductor material region;   a first electrical contact extending from a backside of the sensor to the first electrode;   a second electrical contact extending from a backside of the sensor to the second electrode; and   a sensing region, separated from the first electrode and the second electrode, and capable of interacting with the chemical species to change a measurable property of the chemical sensor.   
     
     
         30 . The chemical sensor of  claim 29 , further comprising a third electrode, wherein the first electrode is a source electrode, the second electrode is a drain electrode and the third electrode is a gate electrode. 
     
     
         31 . A method of detecting chemical species comprising:
 exposing a FET-based chemical sensor to a medium comprising chemical species; and   measuring changes in drain current of the sensor resulting from adsorption of the chemical species on a sensing region separated from the gate electrode to detect chemical species.   
     
     
         32 - 39 . (canceled)