Title :
Process for enhancement/depletion-mode GaAs/InGaAs/AlGaAs pseudomorphic MODFETs using selective wet gate recessing
Author :
Tong, Michael ; Nummila, K. ; Seo, Ja-Won ; Ketterson, Andrew ; Adesida, I.
Author_Institution :
Illinois Univ., Urbana, IL, USA
Abstract :
A process for enhancement/depletion (E/D)-mode GaAs/InGaAs/AlGaAs pseudomorphic modulation-doped filed-effect transistors (MODFETs) using citric acid:H2O2 solutions for selective wet gate recessing has been developed. Extrinsic DC transconductances gm as high as 450 and 600 mS/mm, and unity current-gain cutoff frequencies ft of 75 and 66 GHz at room temperature have been achieved for 0.3 mu m gate-length depletion-mode MODFET (DFET) and enhancement-mode MODFET (EFET), respectively. Standard deviations for threshold voltage and transconductance of less than 16 mV and 25 mS/mm, respectively, have been achieved for both the DFETs and EFETs. Ring oscillators fabricated in direct-coupled FET logic technology have exhibited a propagation delay of 13 ps at room temperature.
Keywords :
III-V semiconductors; aluminium compounds; etching; field effect integrated circuits; gallium arsenide; high electron mobility transistors; indium compounds; semiconductor technology; solid-state microwave devices; 0.3 micron; 13 ps; 450 mS; 600 mS; 66 GHz; 75 GHz; DC transconductances; GaAs-InGaAs-AlGaAs; H 2O 2; MODFETs; citric acid-H 2O 2 solutions; cutoff frequencies; direct-coupled FET logic technology; enhancement/depletion-mode; gate-length; propagation delay; pseudomorphic modulation-doped filed-effect transistors; ring oscillators; selective wet gate recessing; semiinsulating GaAs substrate; threshold voltage;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:19921039
