Preparation And Application Of Silicon Nanowire Ion Sensor

Ion-sensitive field-effect transistors（ISFETs）fabricated by advanced complementary metal-oxide-semiconductor（CMOS）process technology have become a direction of increasing interest due to their ease of miniaturization,easy hybrid integration with logic circuits,and low cost.ISFET is divided into traditional gate ISFET and extended gate ISFET in structure.When the traditional gate sensor works,the fine gate oxide will be directly exposed to the detection environment,resulting in low stability,high noise and poor repeatability of traditional gate ISFET.Compared with the traditional gate ISFET,the extended gate ISFET has the advantages of high stability and low noise,but the separation structure leads to low device integration.Studies have shown that the combination of extended-gate ISFET sensors with advanced node devices can not only reduce the impact of biochemical detection on the device,but also improve detection sensitivity,reduce device size,increase device integration,reduce sensor operating voltage,and reduce device loss.In this paper,a traditional gated SiNW sensor is prepared and the whole process of its modification and detection is explored to solve the problem of difficult detection of ultra-low concentration biological samples.However,traditional gate devices have inevitable drawbacks,so an extended sensing gate silicon nanowire ion-sensitive field effect transistor（ESG SiNWISFET）sensor based on 10nm node fin field effect transistor（FinFET）process is designed.The main research contents and conclusions of this paper are as follows:1、In this paper,a traditional gate SiNW FET sensor is fabricated with high efficiency using a self-aligned sidewall transfer（SIT）process,and the source-drain parasitic resistance of the sensor is reduced by metal silicide and implantation techniques.After the modification of calmodulin on the SiNW FET sensor,the high-sensitivity,high-specificity,real-time label-free detection of Ca²⁺was successfully achieved,and the detection limit of Ca²⁺was lower than 100 f Mol/L,and the detection results far exceeded the traditional electrochemical detection method.2、Aiming at the problem that traditional gate devices are easily damaged,an extended gate device is designed.The ESG SiNWISFET sensor fabricated on the10nm node FinFET process is the product of combining the FinFET device with the ISFET concept.The successfully prepared device is easy to test,and the Fin morphology of the device is good and the size is ultra-thin.The thickness of the gate oxide film is also optimized,and a device with good performance is obtained.3、The newly prepared ESG SiNWISFET sensor has a sensitivity as high as90.2 m V/p H.4、Sensor stability is an important basis for judging the excellent performance of the device.After the stability judgment experiment,under the same processing conditions,the sensitivity reduction of the newly designed ESG SiNWISFET sensor is 50%of that of the conventional gate SiNW FET sensor.5、Regarding the difficulty of reducing the power consumption of the sensor,the operating voltage of the successfully prepared ESG SiNWISFET sensor is lower than0.8V,which realizes the low power consumption of the device.