Browsing by Author "Wu, Yun-Chi"

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60 GHz broadband Ms-to-CPW hot-via flip chip interconnects
(2007-11-01)
Wu, Wei-Cheng
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Hsu, Li-Han
;
Chang, Edward Yi
;
Kaernfelt, Camilla
;
Zirath, Herbert
In this letter, the microstrip-to-coplanar waveguide (MS-to-CPW) hot-via flip chip interconnect has been experimentally demonstrated to have broadband performance from dc to 67 GHz. The interconnect structures with the hot-via transitions were first designed and optimized by using the electromagnetic simulation tool. Three types of designs were investigated in this letter. The interconnect structures were then fabricated and radio frequency (RF) tested up to 67 GHz. The optimized interconnect structure with the compensation design demonstrated excellent RF characteristics with the insertion loss less than 0.5 dB and the return loss below 18 dB over a very broad bandwidth from dc to 67 GHz. This is to our knowledge the best result reported for this frequency range.
An Al(2)O(3) AlGaAs/InGaAs Metal-Oxide-Semiconductor PHEMT SPDT Switch with Low Control Currents for Wireless Communication Applications
(2010-01-01)
Wu, Yun-Chi
;
Lin, Yueh-Chin
;
Chang, Edward Yi
;
Lee, C. T.
;
Kei, Chi-Chung
An AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high electron mobility transistor (MOS-PHEMT) single- pole-double-throw (SPDT) switch using Al(2)O(3) high-k gate dielectric by atomic layer deposition is fabricated. The MOS-PHEMT exhibited a comparable dc performance and a much lower gate current compared to PHEMT. Radio-frequency (rf) test shows that the MOS-PHEMT switch has an insertion loss of less than 0.5 dB, an isolation larger than 30 dB, a return loss larger than 15 dB, and an input power for 1 dB compression of 31.4 dBm at 2.5 GHz. Overall, MOS-PHEMT monolithic microwave integrated circuits switches have comparable rf performance to PHEMT switches but with much lower dc power consumption. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3380967] All rights reserved.
An Al2O3 AlGaAs/InGaAs Metal-Oxide-Semiconductor PHEMT SPDT Switch with Low Control Currents for Wireless Communication Applications
(2010-01-01)
Wu, Yun-Chi
;
Lin, Yueh-Chin
;
Chang, Edward Yi
;
Lee, C. T.
;
Kei, Chi-Chung
An AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high electron mobility transistor (MOS-PHEMT) single- pole-double-throw (SPDT) switch using Al2O3 high-k gate dielectric by atomic layer deposition is fabricated. The MOS-PHEMT exhibited a comparable dc performance and a much lower gate current compared to PHEMT. Radio-frequency (rf) test shows that the MOS-PHEMT switch has an insertion loss of less than 0.5 dB, an isolation larger than 30 dB, a return loss larger than 15 dB, and an input power for 1 dB compression of 31.4 dBm at 2.5 GHz. Overall, MOS-PHEMT monolithic microwave integrated circuits switches have comparable rf performance to PHEMT switches but with much lower dc power consumption. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3380967] All rights reserved.
Design and Fabrication of 0/1-Level RF-Via Interconnect for RF-MEMS Packaging Applications
(2010-02-01)
Hsu, Li-Han
;
Wu, Wei-Cheng
;
Chang, Edward Yi
;
Zirath, Herbert
;
Wu, Yun-Chi
This paper presents the parametric study of RF-via (0-level) and flip-chip bump (1-level) transitions for applications of packaging coplanar RF-MEMS devices. The key parameters were found to be the bumps' and vias' positions and the overlap of the metal pads, which should be carefully considered in the entire two levels of packages. The length of the backside transmission line, determining the MEMS substrate area, showed minor influence on the interconnect performance. With the experimental results, the design rules have been developed and established. The optimized interconnect structure for the two levels of packages demonstrates the return loss beyond 15 dB and the insertion loss within 0.6 dB from dc to 60 GHz.
Design of Flip-Chip Interconnect Using Epoxy-Based Underfill Up to V-Band Frequencies With Excellent Reliability
(2010-08-01)
Hsu, Li-Han
;
Wu, Wei-Cheng
;
Chang, Edward Yi
;
Zirath, Herbert
;
Hu, Yin-Chu
This study demonstrates a flip-chip interconnect with epoxy-based underfill (epsilon(r) = 3.5 and tan delta = 0.02 at 10 MHz) for packaging applications up to V-band frequencies. To achieve the best interconnect performance, both the matching designs on GaAs chip and Al(2)O(3) substrate were adopted with the underfill effects taken into consideration. The optimized flip-chip interconnect showed excellent performance from dc to 67 GHz with return loss below -20 dB and insertion loss less than 0.6 dB. Furthermore, the dielectric loss induced by the underfill was extracted from measurement and compared with the simulation results. The reliability tests including 85 degrees C/85 % relative humidity test, thermal cycling test, and shear force test were performed. For the first time, the S-parameters measurement was performed to check the flip-chip reliability, and no performance decay was observed after 1000 thermal cycles. Moreover, the mechanical strength was improved about 12 times after the underfill was applied. The results show that the proposed flip-chip architecture has excellent reliability and can be applied for commercial applications.
Evaluation of Electrical Characteristics of the Copper-Metallized SPDT GaAs Switches at Elevated Temperatures
(2008-09-01)
Wu, Yun-Chi
;
Chang, Edward Yi
;
Lin, Yueh-Chin
;
Hsu, Li-Han
;
材料科學與工程學系
Copper-metallized AlGaAs/InGaAs pseudomophic high-electron mobility transistor single-pole-double-throw (SPDT) switches utilizing platinum (Pt, 70 nm) as the diffusion barrier have been studied and demonstrated. As compared with the Au-metallized switches, the Cu-metallized SPDT switches exhibited comparable performance with insertion loss less than 0.5 dB, return loss larger than 20 dB, isolation larger than 35 dB, and the input power for 1-dB compression (input P-1 (dB)) of 28.3 dBm at 2.5 GHz. In order to evaluate the temperature-dependent impact on dc and RF characteristics of the copper-metallized switches for high-temperature applications, the switches have been tested at different temperatures. The device exhibits low thermal threshold coefficients (delta V-th/delta T) of -0.25 mV/K from 300 K to 500 K, good microwave performance at 380 K with insertion loss less than 0.5 dB, isolation higher than 40 dB, and the input power for I-dB compression (input P-1 (dB)) of 28.45 dBm at 2.5 GHz. To test the thermal stability of the Pt diffusion barrier, these switches were annealed at 250 degrees C for 20 h. After the annealing, the switches showed no degradation of the dc characteristics. In addition, after a high temperature storage life environment test at 150 degrees C, these copper-metallized switches remained capable of excellent power handling. To test the operation reliability of the copper-metallized switches, the copper-metallized switches were subjected to ON/OFF (control voltage = +3/0 V exchange) stress test for 24 h at room temperature. The devices maintained excellent RF characteristics after the stress test. Consequently, it is successfully demonstrated through these tests that copper metallization using Pt as the diffusion barrier could be applied to the GaAs monolithic microwave integrated circuit switch fabrication with good RF performance, high-temperature characteristics, and reliability.
Study of the inversion behaviors of Al(2)O(3)/In(x)Ga(1-x)As metal-oxide-semiconductor capacitors with different In contents
(2010-01-01)
Wu, Yun-Chi
;
Chang, Edward Yi
;
Lin, Yueh-Chin
;
Kei, Chi-Chung
;
Hudait, Mantu K.
In(x)Ga(1-x)As III-V compound semiconductor metal-oxide-semiconductor field-effect transistors have become a popular topic recently due to the higher drift velocity, and lower effective mass of the In(x)Ga(1-x)As materials. The impact of In content on the accumulation and inversion behaviors of the Al(2)O(3)/In(x)Ga(1-x)As capacitors is investigated in this study. For the various In(x)Ga(1-x)As materials studied, the Al(2)O(3)/InAs MOS system showed the strongest inversion phenomena due to the shorter response time of minority carrier of InAs compared to other In(x)Ga(1-x)As materials. Also, very low gate leakage current in the 10(-8) A/cm(2) range was observed for these capacitors. These results demonstrate that Al(2)O(3)/InAs MOS system with strong inversion phenomena and low leakage gate current is potential candidate for future high-performance low power logic MOSFET applications. (C) 2009 Elsevier Ltd. All rights reserved.
Study of the inversion behaviors of Al2O3/InxGa1-xAs metal-oxide-semiconductor capacitors with different In contents
(2010-01-01)
Wu, Yun-Chi
;
Chang, Edward Yi
;
Lin, Yueh-Chin
;
Kei, Chi-Chung
;
Hudait, Mantu K.
InxGa1-xAs III-V compound semiconductor metal-oxide-semiconductor field-effect transistors have become a popular topic recently due to the higher drift velocity, and lower effective mass of the InxGa1-xAs materials. The impact of In content on the accumulation and inversion behaviors of the Al2O3/InxGa1-xAs capacitors is investigated in this study. For the various InxGa1-xAs materials studied, the Al2O3/InAs MOS system showed the strongest inversion phenomena due to the shorter response time of minority carrier of InAs compared to other InxGa1-xAs materials. Also, very low gate leakage current in the 10(-8) A/cm(2) range was observed for these capacitors. These results demonstrate that Al2O3/InAs MOS system with strong inversion phenomena and low leakage gate current is potential candidate for future high-performance low power logic MOSFET applications. (C) 2009 Elsevier Ltd. All rights reserved.