de Vreede Lennart J, Ying Cuifeng, Houghtaling Jared, Figueiredo Da Silva Jacqueline, Hall Adam R, Lovera Andrea, Mayer Michael
Biophysics group, Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland.
Nanotechnology. 2019 Jun 28;30(26):265301. doi: 10.1088/1361-6528/ab0e2a. Epub 2019 Mar 8.
This paper presents a maskless method to manufacture fused silica chips for low-noise resistive-pulse sensing. The fabrication includes wafer-scale density modification of fused silica with a femtosecond-pulsed laser, low-pressure chemical vapor deposition (LPVCD) of silicon nitride (SiN ) and accelerated chemical wet etching of the laser-exposed regions. This procedure leads to a freestanding SiN window, which is permanently attached to a fused silica support chip and the resulting chips are robust towards Piranha cleaning at ∼80 °C. After parallel chip manufacturing, we created a single nanopore in each chip by focused helium-ion beam or by controlled breakdown. Compared to silicon chips, the resulting fused silica nanopore chips resulted in a four-fold improvement of both the signal-to-noise ratio and the capture rate for signals from the translocation of IgG proteins at a recording bandwidth of 50 kHz. At a bandwidth of ∼1 MHz, the noise from the fused silica nanopore chips was three- to six-fold reduced compared to silicon chips. In contrast to silicon chips, fused silica chips showed no laser-induced current noise-a significant benefit for experiments that strive to combine nanopore-based electrical and optical measurements.
本文提出了一种用于制造用于低噪声电阻脉冲传感的熔融石英芯片的无掩膜方法。制造过程包括用飞秒脉冲激光对熔融石英进行晶圆级密度改性、氮化硅（SiN）的低压化学气相沉积（LPVCD）以及对激光曝光区域进行加速化学湿法蚀刻。该过程会形成一个独立的SiN窗口，该窗口永久性地附着在熔融石英支撑芯片上，并且所得芯片对约80°C的王水清洗具有耐受性。在并行芯片制造之后，我们通过聚焦氦离子束或通过可控击穿在每个芯片中创建了一个单一纳米孔。与硅芯片相比，所得的熔融石英纳米孔芯片在50 kHz记录带宽下，IgG蛋白转位信号的信噪比和捕获率都提高了四倍。在约1 MHz的带宽下，熔融石英纳米孔芯片的噪声比硅芯片降低了三到六倍。与硅芯片不同，熔融石英芯片没有激光诱导的电流噪声——这对于努力结合基于纳米孔的电学和光学测量的实验来说是一个显著的优势。
