Chemically sensitive sensor with lightly doped drains

• US 8,653,567 B2
• Filed: 06/30/2011
• Issued: 02/18/2014
• Est. Priority Date: 07/03/2010
• Status: Active Grant

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Fife, Keith
• Primary Examiner(s): YEUNG LOPEZ, FEIFEI
• Application Number:
  US13/173,793
• Publication Number:
  US 20120001235A1
• Time in Patent Office: 964 Days
• Field of Search: None
• US Class Current: 257/252
• CPC Class Codes: G01N 27/414 Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS
• CPC Class Codes: G01N 27/4145 specially adapted for biomolecules, e.g. gate electrode with immobilised receptors
• CPC Class Codes: H01L 29/6659 with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET
• CPC Class Codes: H01L 29/788 with floating gate H01L29/78391 takes precedence
• CPC Class Codes: H10B 41/00 Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates

Abstract

A chemically sensitive sensor with a lightly doped region that affects an overlap capacitance between a gate and an electrode of the chemical sensitive sensor. The lightly doped region extends beneath and adjacent to a gate region of the chemical sensitive sensor. Modifying the gain of the chemically sensitive sensor is achieved by manipulating the lightly doped region under the electrodes.

Claims

1. A chemically sensitive sensor, comprising:

a floating gate electrically coupled to a gate electrode on a substrate;

a drain terminal connection;

a source terminal connection;

a pair of electrodes formed on the substrate and one electrode of the pair on either side of the gate electrode;

a pair of doped regions in the substrate, one of the pair of doped regions including a lightly doped region and a highly doped region, wherein the lightly doped region extends beneath a respective one of the electrodes and the highly doped region of each pair extends to couple respectively with the drain terminal and the source terminal.

2. The chemically sensitive sensor of claim 1, further comprising:

a microwell to accept biological material.

3. The chemically sensitive sensor of claim 1, wherein the microwell has an oxide layer at the bottom of the well adjacent to the floating gate.

4. The chemically sensitive sensor of claim 1, wherein one of the pair of electrodes acts as a reference electrode and as a barrier or well for charge packets.

5. The chemically sensitive sensor of claim 1, wherein one of the pair of electrodes acts as a diffusion electrode and facilitates charge packets.