微机械生化传感器

自从Clark和Lyons在1962年研制出第一个生物传感器以来，探测各种生物和化学分子的生化传感器相继问世。这类传感器的基本原理是通过生化敏感层，被分析分子在敏感层上的物理或化学吸附被换能器转化为电信号。在众多的设计中，将活泼的生化敏感材料涂镀在硅器件表面是一个最有新意的设想。以往的硅生化传感器多设计为膜片式，器件的灵敏度受到限制。硅微机械悬臂梁是一种灵敏度极高的器件，近年来在传感器领域受到关注。文章总结了目前世界上硅基微悬梁生化传感器的最新发展动态。对几种硅悬臂梁的设计方法和工作原理进行了讨论，并给出了几种新型微生化气体和液体传感器检测不同有机分子和生物分子的结果。     

U形阵列式微机械悬臂梁的研究

为提高悬臂梁的分辨率，实现悬臂梁的多功能性，设计了一种U形阵列式压阻悬臂梁.从理论上对悬臂梁的应力、噪声和灵敏度进行分析，优化了悬臂梁及力敏电阻的几何尺寸.选用多晶硅为力敏材料，基于硅微机械加工技术，制备U形阵列式悬臂梁.测量悬臂梁的噪声及灵敏度，得到多晶硅力敏材料的Hooge因子和应变灵敏度系数，分别为3×10^-3和27.在6V偏压和1000Hz测量带宽条件下，计算悬臂梁的最小可探测位移为0.5nm.同时对多晶硅力敏电阻噪声的产生机理进行了探讨. 关键词： 悬臂梁 噪声 灵敏度 最小可探测位移     

微机械生化传感器

自从Clark和Lyons在1962年研制出第一个生物传感器以来,探测各种生物和化学分子的生化传感器相继问世.这类传感器的基本原理是通过生化敏感层,被分析分子在敏感层上的物理或化学吸附被换能器转化为电信号.在众多的设计中,将活泼的生化敏感材料涂镀在硅器件表面是一个最有新意的设想.以往的硅生化传感器多设计为膜片式,器件的灵敏度受到限制.硅微机械悬臂梁是一种灵敏度极高的器件,近年来在传感器领域受到关注.文章总结了目前世界上硅基微悬臂梁生化传感器的最新发展动态.对几种硅悬臂梁的设计方法和工作原理进行了讨论,并给出了几种新型微生化气体和液体传感器检测不同有机分子和生物分子的结果.     

NOISE AND SENSITIVITY IN POLYSILICON PIEZORESISTIVE CANTILEVERS

Piezoresistive cantilevers with dimensions of 200×50×1.8μm³ have been fabricated from polycrystalline silicon using reactive ion etching (RIE) and back etching processes. Full Wheatstone bridges have been designed symmetrically on-chip, with two resistors placed on the cantilevers and two resistors on the substrate. The differential measurements of the two cantilevers can reduce the thermal shift of the signal in the system and the external noise in the laboratory. The characteristics of the fabricated cantilevers have been analysed by measuring the noise and the sensitivity. The measured noise spectra show that the 1/f noise is the dominant noise source at low frequencies. With the linear relation between 1/f noise and bias voltages, the Hooge factor (α) was calculated to be 0.0067. The 1/f noise was explained in terms of a lattice scattering model, which occurs in the depletion region of the grains. The displacement sensitivity of the cantilevers ((ΔR)/Rz^-1) was calculated to be 1×10^-6nm^-1 by measuring the resistance change and the vertical deflection of the cantilever. The gauge factor of the piezoresistive cantilever was calculated to be 19. At a 3 V bias voltage and 1000 Hz measurement bandwidth, 1 nm of minimum detectable deflection has been obtained.