Development of human IgE biosensor using Sezawa-mode SAW devices

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• 作者：Ying-Chung Chen^a ; Wei-Tsai Chang^a ; Chien-Chuan Cheng^b ; ^{chengccc@dlit.edu.tw" class="auth_mail} ; Jing-Yi Shen^a ; Kuo-Sheng Kao^c
• 关键词：Sezawa-mode ; SAW ; IgE ; Allergy biosensor
• 刊名：Current Applied Physics
• 出版年：April, 2014
• 年：2014
• 卷：14
• 期：4
• 页码：608-613
• 全文大小：1644 K

文摘

This paper reports Sezawa-mode surface acoustic wave (SAW) devices with via-isolated cavity to construct the allergy biosensor. To fabricate Sezawa-mode SAW devices, the RF magnetron sputtering method for the growth of piezoelectric ZnO thin films are adopted and influences of the sputtering parameters are investigated. The optimal substrate temperature of 300聽掳C, RF power of 120聽W and sputtering pressure of 2聽Pa were used to deposit piezoelectric ZnO films with a smooth surface, uniform grain size and strongly c-axis-orientated crystallization. A back-etched SAW resonator is used in this study. The wet etching of (100)-oriented silicon wafers is used to form a back-side cavity which is critical to the formation of a hopper cavity for holding bio-analytes. The remaining membrane structure silicon thickness was 25聽渭m. In this report, the chrome (Cr, 12聽nm)/gold (Au, 66聽nm) layer was initially deposited onto the sensing area of SAW devices as the binding layer for biochemical sensor. The resonance frequency of the Sezawa-mode SAW device is 1.497聽GHz. The maximum sensitivity of the Sezawa-mode is calculated to be 4.44聽脳聽10⁶聽cm²/g for human immunoglobulin-E (IgE) detection. The stability for human IgE detection is calculated to be 80% and the variation of the stability 卤3% was obtained after several tests.