Department of Electrical Engineering, College of Information Science and Technology KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea.
Nanotechnology. 2011 Apr 1;22(13):135502. doi: 10.1088/0957-4484/22/13/135502. Epub 2011 Feb 22.
A nanogap embedded complementary metal oxide semiconductor (NeCMOS) is demonstrated as a proof-of-concept for label-free detection of DNA sequence. When a partially carved nanogap between a gate and a silicon channel is filled with charged biomolecules, the gate dielectric constant and charges are changed. When the gate oxide thickness reduces, the threshold voltage is significantly affected by a change of the charges, whereas it is scarcely influenced by a change of the dielectric constant. In the case of DNA, those two factors act on the threshold voltage oppositely in an n-channel NeCMOS but collaboratively in a p-channel NeCMOS because of the negative charges of DNA. Hence, a p-channel NeCMOS with a thin gate oxide is more attractive for DNA detection because it enhances the shift of threshold voltage; that is, it improves the sensitivity of DNA detection. In addition, the shift of threshold voltage according to the nanogap length is also investigated and the longer nanogap shows more shift of the threshold voltage.
一种嵌入式纳米间隙互补金属氧化物半导体（NeCMOS）被证明是用于无标记检测 DNA 序列的概念验证。当栅极和硅通道之间的部分雕刻纳米间隙被带电生物分子填充时，栅介质常数和电荷会发生变化。当栅氧化层厚度减小时，电荷变化会显著影响阈值电压，而介电常数的变化几乎不会影响阈值电压。在 DNA 的情况下，由于 DNA 的负电荷，这两个因素在 n 通道 NeCMOS 中对阈值电压的作用相反，但在 p 通道 NeCMOS 中协同作用。因此，由于薄栅氧化层，p 通道 NeCMOS 更适合用于 DNA 检测，因为它增强了阈值电压的变化，即提高了 DNA 检测的灵敏度。此外，还研究了根据纳米间隙长度的阈值电压变化，并且较长的纳米间隙显示出更大的阈值电压变化。
