Title :
Effect of Gate Sinking on the Device Performance of the InGaP/AlGaAs/InGaAs Enhancement-Mode PHEMT
Author :
Chu, L.H. ; Chang, E.Y. ; Chang, L. ; Wu, Y.H. ; Chen, S.H. ; Hsu, H.-T. ; Lee, T.L. ; Lien, Y.C. ; Chang, C.Y.
Author_Institution :
Dept. of Mater. Sci. & Eng., Nat. Chiao Tung Univ., Hsinchu
Abstract :
An enhancement-mode InGaP/AlGaAs/InGaAs pseudomorphic high-electron mobility transistor using platinum (Pt) as the Schottky contact metal was investigated for the first time. Following the Pt/Ti/Pt/Au gate metal deposition, the devices were thermally annealed at 325 degC for gate sinking. After the annealing, the device showed a positive threshold voltage (Vth) shift from 0.17 to 0.41 V and a very low drain leakage current from 1.56 to 0.16 muA/mm. These improvements are attributed to the Schottky barrier height increase and the decrease of the gate-to-channel distance as Pt sinks into the InGaP Schottky layer during gate-sinking process. The shift in the Vth was very uniform across a 4-in wafer and was reproducible from wafer to wafer. The device also showed excellent RF power performance after the gate-sinking process
Keywords :
Schottky barriers; aluminium compounds; annealing; buried layers; gallium compounds; gold alloys; high electron mobility transistors; indium compounds; leakage currents; platinum alloys; semiconductor technology; titanium alloys; 325 C; InGaP-AlGaAs-InGaAs; Pt-Ti-Pt-Au; Schottky barrier height; Schottky contact metal; buried gate; enhancement-mode PHEMT; gate metal deposition; gate sinking; gate-to-channel distance; pseudomorphic high-electron mobility transistor; thermal annealing; Annealing; Gold; HEMTs; Indium gallium arsenide; Leakage current; MODFETs; PHEMTs; Platinum; Schottky barriers; Threshold voltage; Buried gate; InGaP; enhancement-mode (E-mode); platinum (Pt); pseudomorphic high-electron mobility transistor (PHEMT); single voltage supply;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2006.889238
