CHEMICALLY SENSITIVE SENSOR WITH LIGHTLY DOPED DRAINS

摘要

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.

主权项

1. A method of making a chemically sensitive sensor, comprising:
forming a substrate with a first conductivity type of dopant; building an epitaxial layer using the same conductivity type dopant used to form the substrate, but made less dense than the dopant on the substrate; forming an electrode layer on the epitaxial layer formed from a different, second conductivity type of dopant than the first conductivity type of dopant used to form the substrate, wherein the density of dopant on both the electrode layer and the substrate are similar; masking and etching the electrode layer to produce gates and electrodes; creating a first lightly doped region adjacent to one of the electrodes using a multidirectional implant technique, wherein the first lightly doped region is formed from a dopant of a conductivity type opposite the epitaxial layer dopant; producing diffusion nodes that are self-aligned with the electrodes next to the gates, a first of said diffusion nodes contiguous with the first lightly doped region, from a dopant of a conductivity type similar to the gates, electrodes, and lightly doped region; and forming a floating gate electrode, electrodes above the diffusion area, and contacts for electrodes by alternating layers of insulation, dielectric, conductive and metal layers.