Comparison of the characteristics of semiconductor gas sensors with different transducers fabricated on the same substrate

Gyuweon Jung, Wonjun Shin, Seongbin Hong, Yujeong Jeong, Jinwoo Park, Donghee Kim, Jong Ho Bae, Byung Gook Park, Jong Ho Lee

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

The semiconductor-type gas sensor consists of a transducer and a sensing material. Most of the research on the sensor has focused on sensing materials. In this study, the characteristics of gas sensors using three different transducers (MOSFET, resistor, and TFT) are compared. For a fair comparison, the three types of gas sensors are fabricated through the same process on one chip and have the same sensing material. Indium oxide (In2O3) and NO2 gas are used as the sensing material and the target gas, respectively. The low-frequency noise (LFN) characteristics, response, signal to noise ratio (SNR), and limit of detection (LOD) of the three types of gas sensors are investigated and compared. Since the MOSFET-type gas sensor uses crystalline Si as the current path, the current normalized noise of the sensor is ∼105 smaller than that of the resistor- and TFT-type gas sensors using polycrystalline In2O3 as the current path. However, when reacting to 500 ppb NO2 gas, the response is the smallest in the MOSFET-type gas sensor and the largest in the TFT-type gas sensor (MOSFET: ∼2.3 × 102, resistor: 3.3 × 103 and TFT: ∼3.2 × 107). The SNR is large in order of TFT-, MOSFET-, resistor-type gas sensor over the entire range of measured gas concentrations (20 ∼ 500 ppb). The LODs of TFT-, MOSFET- and resistor-type gas sensors are 0.017, 0.300, and 26.3 ppb respectively. Considering the response, SNR and LOD, the TFT-type gas sensor is the best among the three-types of sensors.

Original languageEnglish
Article number129661
JournalSensors and Actuators, B: Chemical
Volume335
DOIs
StatePublished - 15 May 2021
Externally publishedYes

Keywords

  • Limit of detection (LOD)
  • Low-frequency noise (LFN)
  • MOSFET-type gas sensor
  • Resistor-type gas sensor
  • Sensing mechanism
  • Signal to noise ratio (SNR)
  • TFT-type gas sensor

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