T-Gate Fabrication of InP-Based HEMTs Using PMGI/ZEP520A/PMGI/ZEP520A Stacked Resist

• Published in: Chinese Journal of Electronics Vol. 25; no. 3; pp. 448 - 452
• Main Authors: Zhong, Yinghui, Zang, Huaping, Wang, Haili, Sun, Shuxiang, Li, Kaikai, Ding, Peng, Jin, Zhi
• Format: Journal Article
• Language: English
• Published: Published by the IET on behalf of the CIE 01.05.2016
• Subjects: automatic self‐alignment; EBL; Electron beam lithography (EBL); electron resists; four‐layer resist stack; frequency 249 GHz; frequency 415 GHz; gate‐foot; gate‐head; HEMT; HEMTs; HEMT器件; high electron mobility transistors; High electron mobility transistors (HEMTs); III‐V semiconductors; indium compounds; InP; InP基; maximum extrinsic transconductance; nanometer regime; PMGI; single‐step electron beam lithography; T‐gate; T‐gate fabrication; wide band gap semiconductors; ZEP520A; 制造; 层叠; 最高振荡频率; 高电子迁移率晶体管; electron resists; maximum extrinsic transconductance; gate-foot; high electron mobility transistors; HEMT; T-gate; High electron mobility transistors (HEMTs); indium compounds; single-step electron beam lithography; four-layer resist stack; InP; EBL; frequency 249 GHz; gate-head; Electron beam lithography (EBL); frequency 415 GHz; PMGI; automatic self-alignment; wide band gap semiconductors; ZEP520A; T-gate fabrication; III-V semiconductors; nanometer regime
• ISSN: 1022-4653; 2075-5597
• DOI: 10.1049/cje.2016.05.009

PMGI/ZEP520A/PMGI/ZEP520 A fourlayer resist stack is firstly proposed for T-gates fabrication of InP-based High electron mobility transistors（HEMTs）.Gate-head and gate-foot are exposed in single-step Electron beam lithography（EBL）, which avoids alignment deviation by automatic self-alignment. The newly introduced PMGI at the bottom greatly improves the adhesiveness of ZEP520 A resist with the substrate. The optimal gate-foot length reaches 101 nm for a design of 50 nm gate footprint pattern, and which can be improved to be 66.8nm for 30 nm gate footprint pattern. Finally, Tgates in nanometer regime have been successfully incorporated into InP-based HEMTs fabrication. Benefiting from both the narrow gate-foot and the reduced parasitic gatecapacitance by single-step EBL technique with the fourlayer resist stack, the fabricated devices with gate-foot length of 101 nm demonstrate excellent DC and RF performances： the maximum extrinsic transconductance, the current-gain cutoff frequency and maximum oscillation frequency are 1051 m S/mm, 249 GHz and 415 GHz, respectively.