Patent ID: 8860442

Claim:
A method of determining/adjusting the sensitivity of a biosensor arrangement comprising at least one field effect biosensor, each of the at least one field effect biosensor comprising: a semiconductor substrate comprising a source region, a drain region and a channel region disposed between the source region and the drain region; a gate isolation layer covering the channel region; and a reference electrode disposed over the gate isolation layer such that a electrolytic solution to be sensed can be provided between the reference electrode and the gate isolation layer, the method comprising the following processes carried out for each field effect biosensor: providing an electrolytic solution between the reference electrode and the gate isolation layer; applying a source/drain voltage between the source region and the drain region; varying a reference voltage supplied to the reference electrode over a voltage range; measuring a resulting drain current while varying the reference voltage in order to obtain a corresponding drain current function; and determining the sensitivity of the field effect biosensor based on the reference voltage supplied to the reference electrode and the corresponding drain current function, wherein determining the sensitivity of the field effect biosensor comprises determining an effective transconductance function by differentiating the measured drain current function with respect to the reference voltage supplied, and dividing the determined effective transconductance function by the measured drain current function.