DEPOSITION OF THE CHEMICALLY SENSITIVE POLYMER LAYER ON SGFET GATE BYLASER-INDUCED CHEMICAL-VAPOR POLYMERIZATION

The method of laser-induced chemical-vapour polymerization (LID) has b een tested to deposit a sensing polymer layer of polypyridine on the g ate of a suspended-gate field-effecet transistor (SGFET) gas sensor. M easurements using exposures to organic vapours demonstrate that the SG FET gate located in the narrow (1000 Angstrom) space on the chip can b e chemically modified by this alternative method. Compared with curren tly used electrochemical deposition, the LID method provides very adhe sive films with different physicochemical properties, which gives a wi der choice of chemically sensing polymer layers available for chemical modification of SGFET sensors. (C) 1997 Elsevier Science S.A.