Title :
GaAs metal insulator field effect transistors with excellent intrinsic transconductance and stable drain currents using (NH/sub 4/)/sub 2/Sx chemical treatment
Author :
Remashan, K. ; Bhat, K.N.
Author_Institution :
Dept. of Electr. Eng., Indian Inst. of Technol., Madras, India
Abstract :
Metal insulator semiconductor field effect transistors (MISFETs) and MIS capacitors are fabricated using Al metal-gate and PECVD silicon nitride (Si/sub 3/N/sub 4/) gate-insulator on commercial GaAs epitaxial wafers after treating the channel regions with (NH/sub 4/)/sub 2/S/sub x/. It is shown that the post metallization annealing (PMA) of these devices improves the transconductance and reduces the interface state density (D/sub it/) considerably. This is attributed to the additional passivation effect of hydrogen diffusing to the interface from the Si/sub 3/N/sub 4/ during the PMA. An intrinsic transconductance of 30.7 mS/mm which is 75% of the theoretical maximum limit of 40.5 mS/mm has been achieved using silicon nitride gate insulator thickness of 1100 /spl Aring/. Stability of the drain currents in these devices is demonstrated to be excellent.
Keywords :
III-V semiconductors; MIS capacitors; MISFET; aluminium; annealing; gallium arsenide; interface states; passivation; plasma CVD; silicon compounds; (NH/sub 4/)/sub 2/S; 1100 angstrom; 30.7 mS/mm; Al-Si/sub 3/N/sub 4/-GaAs; MIS capacitors; PECVD gate-insulator; channel regions; chemical treatment; drain currents; interface state density; intrinsic transconductance; metal insulator field effect transistors; passivation effect; post metallization annealing; Annealing; Capacitors; FETs; Gallium arsenide; Insulation; MISFETs; Metal-insulator structures; Metallization; Silicon; Transconductance;
Journal_Title :
Electron Device Letters, IEEE