Deposition of the chemically sensitive polymer layer on SGFET gate by laser-induced chemical-vapour polymerization

The method of laser-induced chemical-vapour polymerization (LID) has been tested to deposit a sensing polymer layer of polypyridine on the gate of a suspended-gate field-effecet transistor (SGFET) gas sensor. Measurements using exposures to organic vapours demonstrate that the SGFET gate located in the narrow (1000 Angstrom) space on the chip can be chemically modified by this alternative method. Compared with currently used electrochemical deposition, the LID method provides very adhesive films with different physicochemical properties, which gives a wider choice of chemically sensing polymer layers available for chemical modification of SGFET sensors. (C) 1997 Elsevier Science S.A.