Mathew Ribu, Sankar A Ravi
School of Electronics Engineering (SENSE), VIT Chennai, Chennai 600127, India.
J Nanosci Nanotechnol. 2018 May 1;18(5):3387-3397. doi: 10.1166/jnn.2018.14642.
In this paper, we present the design and optimization of a rectangular piezoresistive composite silicon dioxide nanocantilever sensor. Unlike the conventional design approach, we perform the sensor optimization by not only considering its electro-mechanical response but also incorporating the impact of self-heating induced thermal drift in its terminal characteristics. Through extensive simulations first we comprehend and quantify the inaccuracies due to self-heating effect induced by the geometrical and intrinsic parameters of the piezoresistor. Then, by optimizing the ratio of electrical sensitivity to thermal sensitivity defined as the sensitivity ratio (υ) we improve the sensor performance and measurement reliability. Results show that to ensure υ ≥ 1, shorter and wider piezoresistors are better. In addition, it is observed that unlike the general belief that high doping concentration of piezoresistor reduces thermal sensitivity in piezoresistive sensors, to ensure υ ≥ 1 doping concentration (p) should be in the range: 1E18 cm-3 ≤ p ≤ 1E19 cm-3. Finally, we provide a set of design guidelines that will help NEMS engineers to optimize the performance of such sensors for chemical and biological sensing applications.
在本文中，我们展示了一种矩形压阻复合二氧化硅纳米悬臂梁传感器的设计与优化。与传统设计方法不同，我们不仅通过考虑其机电响应，还通过纳入自热引起的热漂移对其终端特性的影响来进行传感器优化。通过大量模拟，我们首先理解并量化了由于压阻器的几何和本征参数引起的自热效应导致的误差。然后，通过优化定义为灵敏度比（υ）的电灵敏度与热灵敏度之比，我们提高了传感器性能和测量可靠性。结果表明，为确保υ≥1，更短更宽的压阻器更好。此外，据观察，与一般认为压阻器的高掺杂浓度会降低压阻传感器的热灵敏度的观点不同，为确保υ≥1，掺杂浓度（p）应在以下范围内：1E18 cm-3≤p≤1E19 cm-3。最后，我们提供了一套设计指南，这将有助于纳米机电系统工程师优化此类传感器在化学和生物传感应用中的性能。
