• Ian, Ka Wa
• Missous, Mohamed
• Zawawiand, Mohamad Adzhar Md

Abstract

This work described the fabrication and performances of strained channel In0.52Al0.47As/In0.7Ga0.3As/InP pHEMTs with thermally evaporated Pd/Ti/Au gate metallization. The electrical characteristics of these Pd-gate devices are studied to investigate the effects of changing the Pd metal thickness, annealing temperature and annealing time. Following annealing at 200 °C for 35 min, a 10 nm Pd-gate device displays a VTH of -0.25 V, which is significantly smaller compared to those with Ti/Au gate schemes showing VTH = -0.75 V. A 1 um gate length device exhibits an improved Gm of 580 mS mm-1 (from 500 mS mm-1), a high IDSmax of 400 mA mm-1 (from 330 mA mm -1) and good fT and fmax of 24.5 and 49 GHz commensurate with the 1 μm gate length. All these enhancements are attributed to the controllable gate sinking of Pd. The device shows no significant degradation even after annealing at 230°C for more than 5 h, which implies that the reliability of these Pd-gate structures is excellent. © 2014 IOP Publishing Ltd.

Topics

• impedance spectroscopy
• mass spectrometry
• annealing
• palladium