0.15-µm T-Shaped Gate MODFETs Using BCB as Low-k Spacer

Yoshiharu ANDA, Katsuhiko KAWASHIMA, Mitsuru NISHITSUJI, Tsuyoshi TANAKA

Summary :

We report 0.15-µm T-shaped gate MODFETs using BCB (Benzocyclobutene) as low-k spacer dielectric material. The RF performance of pseudomorphic MODFET was improved by reducing the gate fringing capacitance using low-k material. The BCB film was deposited by plasma CVD technique at 100C and was patterned by lift-off technique. The dielectric constant of BCB film deposited by plasma CVD was confirmed 2.7, which is equal to that of spin-coated BCB, and is 35% lower than that of conventional SiO₂. The leakage current was 4.710^-5 A/cm² at 3.6 MV/cm and was low enough for spacer material. 0.15-µm T-shaped gate MODFETs were fabricated by using BCB spacer and phase-shift lithography technique. More than 20 GHz increase of f_max was obtained in comparison with conventional SiO₂ spacer by reducing the gate fringing capacitance.

• Publication: IEICE TRANSACTIONS on Electronics Vol.E84-C No.10 pp.1323-1327
• Publication Date: 2001/10/01
• Type of Manuscript: Special Section PAPER (Joint Special Issue on Heterostructure Microelectronics with TWHM 2000 (Topical Workshop on Heterostructure Microelectronics 2000))
• Category: Hetero-FETs & Their Integrated Circuits

Authors

Yoshiharu ANDA
Katsuhiko KAWASHIMA
Mitsuru NISHITSUJI
Tsuyoshi TANAKA

Keyword

GaAs,  MODFET,  BCB,  millimeter wave,  low-k