Title: Copper-airbridged low-noise GaAs PHEMT with Ti/WNx/Ti diffusion barrier for high-frequency applications
Authors: Lee, Cheng-Shih
Lien, Yi-Chung
Chang, Edward Yi
Chang, Huang-Choung
Chen, Szu-Houng
Lee, Ching-Ting
Chu, Li-Hsin
Chang, Shang-Wen
Hsieh, Yen-Chang
材料科學與工程學系
友訊交大聯合研發中心
Department of Materials Science and Engineering
D Link NCTU Joint Res Ctr
Keywords: airbridge;copper metallization;diffusion barrier;GaAs;noise figure;pseudomorphic HEMT (PHEMT)
Issue Date: 1-Aug-2006
Abstract: A GaAs pseudomorphic HEMT (PHEMT) with Cu-metallized interconnects was successfully developed. Sputtered WNx was used as the diffusion barrier and Ti was used as the adhesion layer to improve the adhesion between WNx/Cu interface in the thin-metal structure. After copper metallization, the PHEMTs were passivated with silicon nitride to avoid copper oxidation. The Cu-airbridged PHEMT showed the saturation I-DS was 250 mA/mm and the g(m) was 456 mS/mm. The Ti adhesion layer plays a significant role on the g(m) and V-p uniformity of the Cu-metallized PHEMTs. The GaAs PHEMTs with Ti/WNx/Ti/Cu multilayer have better noise figure and associated gain than those of the devices without the Ti adhesion layer. The fabricated Cu-metallized GaAs PHEMT with Ti/WNx/Ti/Cu multilayer has a noise figure of 0.76 dB and an associated gain of 8.8 dB at 16 GHz. The cutoff frequency (f(T)) is 70 GHz when biased at V-DS = 1.5 V. These results show that the Ti/WNx/Ti multilayer can serve as a good diffusion barrier for Cu metallization process of airbridge interconnects on GaAs low-noise PHEMTs.
URI: http://dx.doi.org/10.1109/TED.2006.876578
http://hdl.handle.net/11536/11941
ISSN: 0018-9383
DOI: 10.1109/TED.2006.876578
Journal: IEEE TRANSACTIONS ON ELECTRON DEVICES
Volume: 53
Issue: 8
Begin Page: 1753
End Page: 1758
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