MICROWELL STRUCTURES FOR CHEMICALLY-SENSITIVE SENSOR ARRAYS
Methods and apparatus relating to FET arrays for monitoring chemical and/or biological reactions such as nucleic acid sequencing-by-synthesis reactions. Some methods provided herein relate to improving signal (and also signal to noise ratio) from released hydrogen ions during nucleic acid sequencing reactions.
1 . A sensor, comprising:
an array of chemically-sensitive field effect transistors (chemFETs);
a dielectric layer over the chemFETs in the array, the dielectric layer defining cavities corresponding to sensing surfaces of the chemFETs; and
a conformal layer of sensing material within the cavities, the layer of sensing material coupled to the sensing surfaces of the chemFETs and substantially lining sidewalls of the cavities.
2 . The sensor of claim 1 , wherein the dielectric layer includes at least one of silicon oxide, silicon nitride and silicon oxynitride.
3 . The sensor of claim 1 , wherein the sensing material includes tantalum oxide.
4 . The sensor of claim 1 , wherein the sensing material is a metal oxide or metal nitride selected from one or more of the group of Al 2 O 3 , Ta 2 O 5 , HfO 3 , WO 3 , or mixtures thereof.
5 . The sensor of claim 1 , wherein the sensing material includes forming Al 2 O 3 , and Ta 2 O 5 over the formed Al 2 O 3 .
6 . The sensor of claim 1 , wherein the chemFETs in the array provide signals indicating an ion-concentration in an analyte solution coupled to the floating gate via the cavities.
7 . A sensor, comprising:
an array of chemically-sensitive field effect transistors (chemFETs);
a dielectric layer over the chemFETs in the array, the dielectric layer defining cavities corresponding to sensing surfaces of the chemFETs;
a conformal layer of sensing material within the cavities, the layer of sensing material coupled to the sensing surfaces of the chemFETs and substantially lining sidewalls of the cavities; and
a microfluidic structure in fluid flow communication with the cavities, and arranged to deliver analytes for sequencing.
8 . The sensor of claim 7 , wherein the dielectric layer includes at least one of silicon oxide, silicon nitride and silicon oxynitride.
9 . The sensor of claim 7 , wherein the sensing material includes tantalum oxide.
10 . The sensor of claim 7 , wherein the sensing material is a metal oxide or metal nitride selected from one or more of the group of Al 2 O 3 , Ta 2 O 5 , HfO 3 , WO 3 , or mixtures thereof.
11 . The sensor of claim 7 , wherein the sensing material includes forming Al 2 O 3 , and Ta 2 O 5 over the formed Al 2 O 3 .
12 . The sensor of claim 7 , wherein the chemFETs in the array provide signals indicating an ion-concentration in an analyte solution coupled to the floating gate via the cavities.