Abstract:

A single-chip metamaterial absorber in terahertz band is proposed, which is based on 65 nm complementary metal-oxide semiconductor (CMOS) process. The chip area is approximately 0.60 mm by 0.65 mm and totally contains 75 absorbing cells. The periodic cell of the absorber is made of octagon-splitand square-split ring resonators, which are designed by employing a 3.2μm copper on the top layer in the CMOS technology. The dielectric spacer consists of un-doped silicate glass, silicon carbide and silicon nitride with the total thickness of 9.02μm. On the back of dielectric is made up a short copper line with the thickness of 0.2μm. It has been found that the maximum absorptivity, based on HFSS simulations, has achieved 97.84% at 0.921THz and 95.76% at 1.181THz, respectively. In comparison with other terahertz absorbers fabricated by using gallium arsenide or film technology, this proposed absorber overcomes the compatibility issues appeared in CMOS process. In addition, it is found that this structure can be easily implemented in large scale integrated circuits.

Key words: metamaterial, split ring resonators, terahertz absorber, equivalent circuit, absorptivity