Nardi A, Turchetti M, Britton W A, Chen Y, Yang Y, Dal Negro L, Berggren K K, Keathley P D
Research Laboratory of Electronics, Massachusetts Institute of Technology, 50 Vassar Street, Cambridge, MA 02139, United States of America.
Department of Electronics and Telecommunications, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, I-10129, Italy.
Nanotechnology. 2021 May 14;32(31). doi: 10.1088/1361-6528/abf8de.
Refractory materials exhibit high damage tolerance, which is attractive for the creation of nanoscale field-emission electronics and optoelectronics applications that require operation at high peak current densities and optical intensities. Recent results have demonstrated that the optical properties of titanium nitride, a refractory and CMOS-compatible plasmonic material, can be tuned by adding silicon and oxygen dopants. However, to fully leverage the potential of titanium (silicon oxy)nitride, a reliable and scalable fabrication process with few-nm precision is needed. In this work, we developed a fabrication process for producing engineered nanostructures with gaps between 10 and 15 nm, aspect ratios larger than 5 with almost 90° steep sidewalls. Using this process, we fabricated large-scale arrays of electrically-connected bow-tie nanoantennas with few-nm free-space gaps. We measured a typical variation of 4 nm in the average gap size. Using applied DC voltages and optical illumination, we tested the electronic and optoelectronic response of the devices, demonstrating sub-10 V tunneling operation across the free-space gaps, and quantum efficiency of up to 1 × 10at 1.2m, which is comparable to a bulk silicon photodiode at the same wavelength and three orders of magnitude higher than with nearly identical gold devices. Tests demonstrated that the titanium silicon oxynitride nanostructures did not significantly degrade, exhibiting less than 5 nm of shrinking of the average gap dimensions over few-mareas after 10 h of operation. Our results will be useful for developing the next generation of robust and CMOS-compatible nanoscale devices for high-speed and low-power field-emission electronics and optoelectronics applications.
难熔材料具有高损伤容限，这对于制造纳米级场发射电子器件和光电子器件很有吸引力，这些应用需要在高峰值电流密度和光强度下运行。最近的结果表明，氮化钛这种难熔且与CMOS兼容的等离子体材料的光学特性可以通过添加硅和氧掺杂剂来调节。然而，为了充分利用氮氧化钛（硅）的潜力，需要一种可靠且可扩展的具有纳米级精度的制造工艺。在这项工作中，我们开发了一种制造工艺，用于生产间隙在10至15纳米之间、纵横比大于5且侧壁几乎呈90°陡峭的工程纳米结构。使用该工艺，我们制造了具有纳米级自由空间间隙的大规模电连接蝴蝶结纳米天线阵列。我们测量到平均间隙尺寸的典型变化为4纳米。通过施加直流电压和光照，我们测试了器件的电子和光电子响应，证明了跨自由空间间隙的亚10伏隧穿操作，以及在1.2微米波长处高达1×10的量子效率，这与相同波长下的体硅光电二极管相当，并且比几乎相同的金器件高出三个数量级。测试表明，氮氧化钛硅纳米结构没有明显降解，在运行10小时后，在几平方毫米的面积上平均间隙尺寸收缩小于5纳米。我们的结果将有助于开发用于高速和低功耗场发射电子器件及光电子应用的下一代坚固且与CMOS兼容的纳米级器件。
