Browsing by Author "Tsai, Szu-Ping"

Now showing 1 - 12 of 12

An 80 nm In(0.7)Ga(0.3)As MHEMT with Flip-Chip Packaging for W-Band Low Noise Applications
(2010-01-01)
Wang, Chin-Te
;
Kuo, Chien-I
;
Lim, Wee-Chin
;
Hsu, Li-Han
;
Hsu, Heng-Tung
The fabrication process of an 80 nm In(0.7)Ga(0.3)As MHEMT device with flip-chip packaging on Al(2)O(3) substrate is presented. The flip-chip packaged device exhibited good dc characteristics with high I(DS) = 425 mA/mm and high g(m) = 970 mS/mm at V(DS) = 1.5 V. Besides, the RF performances revealed high gain of 10 dB at 50 GHz and low minimum noise figure (NF(min))below 2 dB at 60 GHz, showing the feasibility of flip-chip packaged In(0.7)Ga(0.3)As MHEMT device for low noise applications at W-band.
An 80 nm In0.7Ga0.3As MHEMT with Flip-Chip Packaging for W-Band Low Noise Applications
(2010-01-01)
Wang, Chin-Te
;
Kuo, Chien-, I
;
Lim, Wee-Chin
;
Hsu, Li-Han
;
Hsu, Heng-Tung
The fabrication process of an 80 nm In0.7Ga0.3As MHEMT device with flip-chip packaging on Al2O3 substrate is presented. The flip-chip packaged device exhibited good dc characteristics with high I-DS = 425 mA/mm and high g(m) = 970 mS/mm at V-DS = 1.5 V. Besides, the RF performances revealed high gain of 10 dB at 50 GHz and low minimum noise figure (NFmin)below 2 dB at 60 GHz, showing the feasibility of flip-chip packaged In0.7Ga0.3As MHEMT device for low noise applications at W-band.
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.
Design, Fabrication, and Reliability of Low-Cost Flip-Chip-On-Board Package for Commercial Applications up to 50 GHz
(2012-03-01)
Hsu, Li-Han
;
Oh, Chee-Way
;
Wu, Wei-Cheng
;
Chang, Edward Yi
;
Zirath, Herbert
This paper presents a flip-chip-on-board (FCOB) packaging technology using a Rogers RO3210 laminate for microwave applications. Compared to the conventional microwave packaging architecture, the proposed FCOB technology skips one level of the ceramic package and thus results in lower reflections and manufacturing costs. To fulfill the small dimension requirement on printed circuit boards, the coplanar waveguide (CPW) transmission line and flip-chip bump were fabricated on a high-k RO3210 board (epsilon(r) = 10.2) with photolithography and electroplating. The GaAs chip patterned with the CPW line was then flip-chip-mounted onto the RO3210 laminate board. This structure displayed excellent performance from dc to 50 GHz with a return loss S-11 greater than 18 dB and insertion loss S-21 less than 0.5 dB. Meanwhile, the flip-chip bonding of the in-house-fabricated In0.52Al0.As-48/In0.6Ga0.4As metamorphic high-electron-mobility transistor devices on RO3210 also displayed excellent gain performance with a small degradation of 1 dB from dc to 40 GHz, showing the potential of implementing microwave integrated circuits on RO3210. To enhance the mechanical reliability, an epoxy-based underfill was injected into the flip-chip assemblies. Thermal cycling tests were performed to test the interconnect reliability, and the results indicated that the samples passed the thermal cycling test at least up to 600 cycles, showing excellent reliability for commercial applications. To the best of the authors' knowledge, this is the first study that evaluates the use of the RO3210 laminate for microwave flip-chip in open literature.
Effective Passivation With High-Density Positive Fixed Charges for GaN MIS-HEMTs
(2017-05-01)
Liu, Shih-Chien
;
Huang, Chung-Kai
;
Chang, Chia-Hua
;
Lin, Yueh-Chin
;
Chen, Bo-Yuan
An effective passivation with high-density positive fixed charges was demonstrated on GaN MIS-HEMTs. The positive fixed charges at the interface between passivation and AlGaN surface can reduce the surface potential and expand the quantum well under Fermi level. Besides, to satisfy charge balance, the net charge density at the AlGaN surface must equal to the 2DEG carrier density. Thus, the positive fixed charges passivation can increase the 2DEG carrier density and improve the switching performance of GaN MIS-HEMTs. In this paper, we demonstrated a high-density positive fixed charges (similar to 2.71 x 10(13) e/cm(-2)) passivation using SiON for GaN MIS-HEMTs. The device with SiON passivation exhibits significant improvements in I-V characteristics and dynamic R-ON compared to the conventional SiN passivated device.
Flip-Chip Packaging of In0.6Ga0.4As MHEMT Device on Low-Cost Organic Substrate for W-Band Applications
(2010)
Lim, Wee Chin
;
Wang, Chin-Te
;
Kuo, Chien-I
;
Hsu, Li-Han
;
Tsai, Szu-Ping
A discrete low noise In0.6Ga0.4As MHEMT device with 150 nm gate length was flip-chip assembled on the low-cost RO3210 organic substrate for wireless communication applications. The measured DC characteristics were very similar before and after flip-chip assembly. The flip-chip packaged MHEMT device showed a high drain current density of 516 mA/mm and a maximum transconductance of 576 mS/mm at a V-DS of 0.8 V. The insertion gain of the flip-chip packaged device was decayed less than 2 dB up to 100 GHz as compared to the data of bare die. Moreover, the measured minimum noise figure was less than 2 dB as measured at V-DS of 0.7 V and V-GS of -0.7 V in the frequency range from 20 to 64 GHz for the device after flip-chip assembly. The excellent performance of the flip-chip packaged MHEMT device demonstrates the feasibility of using low cost organic substrate for high frequency applications up to W band.
Investigation of electrical and thermal properties of multiple AlGaN/GaN high-electron-mobility transistors flip-chip packaged in parallel for power electronics
(2015-03-01)
Tsai, Szu-Ping
;
Hsu, Heng-Tung
;
Tu, Yung-Yi
;
Chang, Edward Yi
;
材料科學與工程學系
This paper demonstrates, for the first time, the potential of using flip-chip packaging to connect multiple AlGaN/GaN high-electron-mobility transistors (HEMTs) in parallel for application in power electronics. The electrical and thermal properties of both the bare and the packaged devices were experimentally investigated via pulsed current-voltage (I-V) measurements. Compared to the bare die, less than one-fifth the thermal resistance (R-th), triple the output current, and one-third the on-resistance (R-on) with temperature insensibility were observed when three transistors were connected in parallel through flip-chip packaging. Superior performance such as this makes flip-chip packaging a potential technology for high power GaN electronic applications. (C) 2015 The Japan Society of Applied Physics
Investigation of the Flip-Chip Package With BCB Underfill for W-Band Applications
(2014-01-01)
Wang, Chin-Te
;
Hsu, Li-Han
;
Wu, Wei-Cheng
;
Hsu, Heng-Tung
;
Chang, Edward Yi
Flip-chip package has great potential for use in millimeter-wave applications. However, the coefficient of thermal expansion mismatch between the chip and the substrate usually generates thermal stresses that fracture the flip-chip structure. The use of underfills with low dielectric loss is essential to improve the mechanical strength and reliability of the flip-chip package. Benzocyclobutene (BCB) was used in this study as the underfill material for the flip-chip structure using the no-flow process. The flip-chip structure with BCB injection provides good RF performance with a return loss of better than 18 dB and an insertion loss of 0.6 dB up to 100 GHz, in addition to a lower dielectric loss. Furthermore, thermal cycle and shear force tests show that the underfill injection can significantly improve the reliability of a flip-chip package.
Performance Enhancement of Flip-Chip Packaged AlGaN/GaN HEMTs by Strain Engineering Design
(2016-10)
Tsai, Szu-Ping
;
Hsu, Heng-Tung
;
Wuerfl, Joachim
;
Chang, Edward Yi
;
材料科學與工程學系
The piezoelectric polarization of the AlGaN/GaN high-electron-mobility transistors (HEMTs) is strongly related to the strain state in the active area. Therefore, understanding the strain behavior inside the channel is crucial to the device electrical performance improvement of devices. This paper, for the first time, reveals the potential of optimizing flip-chip structures with active-region bumps to modulate the strain state of the AlGaN/GaN HEMT for enhancing the piezoelectric effect. The thermo-mechanical strain is observed to be affected by the physical dimensions and the material properties of the package. Thus, incorporating device strain engineering into packaging design will be very important for GaN devices due to their strong piezoelectric effects.
Performance Enhancement of Flip-Chip Packaged AlGaN/GaN HEMTs Using Active-Region Bumps-Induced Piezoelectric Effect
(2014-07-01)
Tsai, Szu-Ping
;
Hsu, Heng-Tung
;
Chiang, Che-Yang
;
Tu, Yung-Yi
;
Chang, Chia-Hua
We experimentally investigated the impact of different bump patterns on the output electrical characteristics of flip-chip (FC) bonded AlGaN/GaN high-electron mobility transistors in this letter. The bump patterns were designed and intended to provide different levels of tensile stress due to the mismatch in the coefficient of thermal expansion between the materials. After FC packaging, a maximum increase of 4.3% in saturation current was achieved compared with the bare die when proper arrangement of the bumps in active region was designed. In other words, a 17% improvement has been observed on the optimized bump pattern over the conventional bump pattern. To the best of our knowledge, this is the first letter that investigates the piezoelectric effect induced by FC bumps leading to the enhancement in device characteristics after packaging.
Performance Enhancement of Flip-Chip Packaged AlGaN/GaN HEMTs Using Active-Region Bumps-Induced Piezoelectric Effect
(2014-07-01)
Tsai, Szu-Ping
;
Hsu, Heng-Tung
;
Chiang, Che-Yang
;
Tu, Yung-Yi
;
Chang, Chia-Hua
We experimentally investigated the impact of different bump patterns on the output electrical characteristics of flip-chip (FC) bonded AlGaN/GaN high-electron mobility transistors in this letter. The bump patterns were designed and intended to provide different levels of tensile stress due to the mismatch in the coefficient of thermal expansion between the materials. After FC packaging, a maximum increase of 4.3% in saturation current was achieved compared with the bare die when proper arrangement of the bumps in active region was designed. In other words, a 17% improvement has been observed on the optimized bump pattern over the conventional bump pattern. To the best of our knowledge, this is the first letter that investigates the piezoelectric effect induced by FC bumps leading to the enhancement in device characteristics after packaging.
Preparation and characterization of thermal-sensitive ferrofluids for drug delivery application
(2007-03-01)
Liu, Ting-Yu
;
Hu, Shang-Hsiu
;
Hu, Sheng-Hsiang
;
Tsai, Szu-Ping
;
Chen, San-Yuan
Novel thermal-sensitive ferro fluids (F127-ferro fluids) consisting of core-shell-type magnetic nanoparticles dispersed in Pluronic F127-containing aqueous solution were prepared. The core (magnet)-shell (Pluronic F127) nanoparticles were synthesized by in situ coprecipitation process, which were characterized using transmission electron microscope, X-ray diffraction and vibrating sample magnetometer. The F127-ferro fluids gelled above the lower critical solution temperatures (LCST) of approximately 23-28 degrees C, which were higher than that of pure Pluronic F127-. fluids ( 21-25 degrees C). The increase in the LCST of the F127 ferro. fluids may be attributed to a result of a physical interaction between the F127 molecules and the core-shell magnetic nanoparticles. (C) 2006 Elsevier B. V. All rights reserved.