| 摘要 |
PURPOSE:To achieve a longer life of a semiconductor ion sensor, by forming a recess surrounded by a polysilicon layer on the top of a gate of an insulated gate type FET to apply an ion selecting substance in the recess. CONSTITUTION:An ion sensitive type FET (ISFET) is made up of a silicon substrate (P-type) 1, an insulating separation layer 5, a source region 2, a drain region 3, a channel stopper layer 4, a source electrode S, a drain electrode D and an insulating material 6. A polysilicon layer 7 is provided thereon to form a groove 8 while a gate electrode G is formed on the bottom thereof and an ion sensitive substance is applied on the electrode G to form a semiconductor ion sensor. Thus, as the working of polysilicon is made on the top surface of the ISFET after it is manufactured in a flat wafer, this simplifies the construction of the sensor thereby achieving a higher producibility. |
