A process for enhancement/depletion (E/D)-mode GaAs/ InGaAs/AlGaAs pseudomorphic modulation-doped field-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 600mS/mm, and unity current-gain cutoff frequencies ft of 75 and 66 GHz at room temperature have been achieved for 0·3 μm 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 25mS/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 13ps at room temperature.
- Field-effect transistors
- Semiconductor devices and materials
ASJC Scopus subject areas
- Electrical and Electronic Engineering