Semiconductor-based field-effect structures for chemical sensing

Abstract

Silicon sensors can be fabricated as small, rugged and reliable chip devices with a broad field of applications in medicine, biotechnology, food analysis and environmental monitoring. Thus, there is an increasing demand in realizing such sensors for the determination of, e.g. chemical and biological quantities in aqueous solutions. By developing semiconductor-based field-effect structures, moreover, their main advantage is due to the combination of both the physical effect as the transducer principle and the deposition of the sensitive layers directly onto the silicon chip. In this work, different sensor types that are originated from the field effect are presented: The capacitive ElS (electrolyte-insulator-semiconductor) sensor is suitable for the pH detection using the capacitance/voltage technique. By immobilizing an additional enzyme layer, e.g. of penicillinase, a biosensor has been realized. Both sensors can be integrated as an EIS sensor array. The utilization of the porous silicon technology offers the possibility of a further miniaturization. The LAPS (light-addressable potentiometric sensor) is based on the identical ElS structure. Here, each measuring point on the surface can be arbitrarily addressed by a probing light. The resulting photocurrent is generated as the sensor signal. This arrangement also allows a two-dimensional mapping of the spatial distribution of ions or molecules.

Chemical and Biological Field‐Effect Sensors for Liquids—A Status Report

“…79,80 In a further approach, the EIS sensor and a thick-film screen-printed reference electrode have been integrated into a hybrid sensor module. 81 These results favor the employment of the PLD process as an alternative deposition method for thin-film pH and chemically sensitive gate insulator materials.…”

“…In order to simultaneously detect both the variation of the pH and penicillin content, an EIS sensor array has been developed (see e.g., Ref. 79). In addition, the cross-sensitivity of a EIS penicillin sensor in combination with a diffusion barrier has been investigated with respect to four different kinds of penicillin, namely penicillin G, ampicillin, amoxicillin, and cloxacillin.…”

Chemical image scanner based on FDM-LAPS☆

“…(2) EIS capacitance sensor [6] and (3) light-addressable potentiometric sensor (LAPS) [7][8][9] are other examples of chemical sensors based on the EIS structure. They are capable of label-free measurement of pH or ions, and are advantageous for miniaturization, integration with the peripheral circuits and fabrication of various structures on their surfaces with the help of microfabrication techniques such as photolithography.…”

Evaluation of a Chip‐Based Thin‐Film / Thick‐Film Sensor Hybrid for (Bio‐)Chemical Analysis

“…Especially, the use of semiconductor-compatible fabrication techniques for preparing these sensors enables the development of cost-effective analytical devices with high reliability and reproducibility [11,12]. In spite of the high flexibility and large variety of the sensing materials (e.g., dielectric materials, enzymes, antigens, antibodies, DNA, cells [13 ± 22]) and transducers, there is still a major obstacle to early commercialisation of the respective sensors or sensor arrays, namely the missing integrated ™on board∫ reference electrode, which can be also fabricated by microelectronic-compatible process steps.…”