The characterization of stacked α-Si/SiGe/α-Si sensing membrane

In this work, the stacked α-Si/SiGe/α-Si film was first used as ion sensing membrane of Electrolyte-Insulator-Semiconductor. All sensing membranes were deposited in low pressure chemical vapor deposition with GeH4 and Si2H6 mixtures. Comparing to α-Si sensing membrane, the characteristics of the α-Si/SiGe/α-Si sensing membrane were studied including pH sensitivity and drift phenomena. The pH sensitivity of α-Si/SiGe/α-Si and α-Si EIS was 83.1 ± 2.1 and 76.8 ± 2.2mV/pH, respectively. However, the drift voltage was a little large and resulted in the unstable sensitivity. A physical model was proposed for the unstable sensitivity phenomena. This unstable phenomenon was eliminated by baking treatment.