| 摘要 |
PURPOSE:To stabilize an output signal by a method wherein gate electrodes of metals of different kinds are provided on the respective gate films of two MOS-type FETs, while a metal electrode operating as a reference electrode is disposed between said electrodes, and the whole surface is covered with a solid electrolyte in a sensor having a construction wherein said MOS-type FETs are set in a differential constitution and a difference between the respective source potentials thereof is taken out. CONSTITUTION:An Si substrate 1 is separated in two by forming isolating regions 2 and 2' on a surface layer part of the substrate 1, source regions 3 and 3' and drain regions 4 and 4' are provided in the regions 2 and 2' respectively, and a gate insulating film 5 is connected on the whole surface including exposed end parts of these regions. Next, a gate electrode G1 of Au and a gate electrode G2 of Pt are fitted thereon so that they correspond to the regions 3 and 4 and 3' and 4' respectively, a reference electrode 6 is provided in a position between said electrodes, the whole surface is covered with a macromolecular gel 7 which is an electrolyte, and the surface of the gel is protected by a gas permeating film F. According to this constitution, a change in the characteristics of the FETs due to temperature is canceled, the effect of external noise is reduced, and further the thickness of the gel layer 7 can be made small. Therefore the permeation of gas becomes fast. |
