Browsing by Author "Chu, L. H."

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Effect of gate sinking on the device performance, of the InGaP/AlGaAs/InGaAs enhancement-mode PHEMT
(2007-02-01)
Chu, L. H.
;
Chang, E. Y.
;
Chang, L.
;
Wu, Y. H.
;
Chen, S. H.
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 degrees C for gate sinking. After the annealing, the device showed a positive threshold voltage (V-th) shift from 0.17 to 0.41 V and a very low drain leakage current from 1.56 to 0.16 mu A/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 V-th 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.
Interfacial reactions of Pt-based Schottky contacts on nGaP
(2008-02-25)
Chu, L. H.
;
Chang, E. Y.
;
Wu, Y. H.
;
Huang, J. C.
;
Chen, Q. Y.
We have investigated the interfacial reaction between platinum and InGaP in a Schottky diode structure. There was a 7.5-nm-thick amorphous layer formed at the interface between Pt and InGaP after metal deposition. After annealing at 325 degrees C for 1 min, this amorphous layer increased to 12.8 nm and the reverse leakage current also decreased. The diffusion of Pt atoms and the crystallization of amorphous layer took place after annealing at 325 degrees C for 10 min. Prolonging the annealing to 3 h led to formation of Ga(2)Pt and GaPt(3) phases in InGaP and Schottky diodes degraded after these new phases were observed. (C) 2008 American Institute of Physics.
SPDT GaAs switches with copper metallized interconnects
(2007-02-01)
Wu, Y. C.
;
Chang, E. Y.
;
Lin, Y. C.
;
Hsu, H. T.
;
Chen, S. H.
Copper metallized AlGaAs/InGaAs psedomophic high-electron-mobility transistor (PHEMT) single-pole-double-throw (SPDT) switches utilizing platinum (Pt, 70 nm) as the diffusion barrier is reported for the first time. In comparison with the An metallized switches, the Cu metallized SPDT switches exhibited comparable performance with insertion loss of I Ss than 0.5 dB, isolation larger than 35 dB and the input power for one dB compression (input P-1 dB) of 27 dBm at 2.5 GHz. These switches were annealed at 250 degrees for 20 It for thermal stability test and showed no degradation of the dc characteristics after the annealing. Also, after 144 h of high temperature storage life (HTSL) environment test, these switches still remained excellent and reliable radio frequency (RF) characteristics. It is successfully demonstrated for the first time that the copper metallization using Pt as the diffusion barrier could be applied to the GaAs monolithic microwave integrated circuits switch fabrication with good RF performance and reliability.