A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency ide...A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency identification(RFID) inlay. The optimization condition for flip-chip bonding was determined from the behavior of bonding strength. Under the optimized condition, the shear strength for the antenna printed with paste-type Ag ink was larger than that for Cu antenna. Furthermore, an identification distance was varied from the antenna materials. Comparing with the Ag antenna pattern, the as-bonded die on Cu antenna showed a larger distance of identification. However, the long-term reliability of inlay using the Cu antenna was decreased significantly as a function of aging time at room temperature because of the bended shape of Cu antenna formed during the flip-chip bonding process.展开更多
High-power and high-reliability GaN/InGaN flip-chip light-emitting diodes （FCLEDs） have been demonstrated by employing a flip-chip design, and its fabrication process is developed. FCLED is composed of a LED die and...High-power and high-reliability GaN/InGaN flip-chip light-emitting diodes （FCLEDs） have been demonstrated by employing a flip-chip design, and its fabrication process is developed. FCLED is composed of a LED die and a submount which is integrated with circuits to protect the LED from electrostatic discharge （ESD） damage. The LED die is flip-chip soldered to the submount, and light is extracted through the transparent sapphire substrate instead of an absorbing Ni/Au contact layer as in conventional GaN/InGaN LED epitaxial designs. The optical and electrical characteristics of the FCLED are presented. According to ESD IEC61000-4-2 standard （human body model）, the FCLEDs tolerated at least 10 kV ESD shock have ten times more capacity than conventional GaN/InGaN LEDs. It is shown that the light output from the FCLEDs at forward current 350mA with a forward voltage of 3.3 V is 144.68 mW, and 236.59 mW at 1.0A of forward current. With employing an optimized contact scheme the FCLEDs can easily operate up to 1.0A without significant power degradation or failure. The li.fe test of FCLEDs is performed at forward current of 200 mA at room temperature. The degradation of the light output power is no more than 9% after 1010.75 h of life test, indicating the excellent reliability. FCLEDs can be used in practice where high power and high reliability are necessary, and allow designs with a reduced number of LEDs.展开更多
A single mode hybrid Ⅲ-Ⅴ/silicon on-chip laser based on the flip-chip bonding technology for on-chip optical interconnection is demonstrated. A single mode Fabry-Perot laser structure with micro-structures on an InP...A single mode hybrid Ⅲ-Ⅴ/silicon on-chip laser based on the flip-chip bonding technology for on-chip optical interconnection is demonstrated. A single mode Fabry-Perot laser structure with micro-structures on an InP ridge waveguide is designed and fabricated on an InP/AIGaInAs multiple quantum well epitaxial layer structure wafer by using i-line lithography. Then, a silicon waveguide platform including a laser mounting stage is designed and fabricated on a silicon-on-insulator substrate. The single mode laser is flip-chip bonded on the laser mounting stage. The lasing light is butt-coupling to the silicon waveguide. The laser power output from a silicon waveguide is 1.3roW, and the threshold is 37mA at room temperature and continuous wave operation.展开更多
High-reflectivity Al-based n-electrode is used to enhance the luminescence properties of InGaN-based 395nm flip-chip near-ultraviolet （UV） light-emitting diodes. The Al-only metal layer could form the Ohmic contact ...High-reflectivity Al-based n-electrode is used to enhance the luminescence properties of InGaN-based 395nm flip-chip near-ultraviolet （UV） light-emitting diodes. The Al-only metal layer could form the Ohmic contact on the plasma etched n-GaN by means of chemical pre-treatment, with the lowest specific contact resistance of 2.211 × 10^-5 Ω. cm2. The AI n-electrodes enhance light output power of the 395 nm flip-chip near-UV light-emitting diodes by more than 33% compared with the Ti/AI n-electrodes. Meanwhile, the electrical characteristics of these chips with two types of n-electrodes do not show any significant discrepancy. The near-field light distribution measurement of packaged chips confirms that the enhanced luminescence is ascribed to the high refleetivity of the Al electrodes in the UV region. After the accelerated aging test for over 1000 h, the luminous degradation of the packaged chips with Al n-electrodes is less than 3%, which proves the reliability of these chips with the Al-based electrodes. Our approach shows a simplified design and fabrication of high-refleetivity n-electrode for flip-chip near-UV light emitting diodes.展开更多
In this paper,we proposed and experimentally demonstrated an 8-channel O-band distributed feedback(DFB)laser array with highly uniform 400 GHz spacing and high output power for optical input/output(I/O)technology.The ...In this paper,we proposed and experimentally demonstrated an 8-channel O-band distributed feedback(DFB)laser array with highly uniform 400 GHz spacing and high output power for optical input/output(I/O)technology.The grating phase is precisely controlled,and an equivalentπphase shift is implemented in the laser cavity via the reconstruction equivalent chirp(REC)technology.Anti-reflection(AR)and high-reflection(HR)films are coated on the front and rear facets,respectively,to enhance output power.The equivalentπphase shift is strategically placed near the HR film facet to improve the yield of the single longitudinal mode.Operating with a 400 GHz wavelength spacing,the proposed DFB laser array meets the continuous wave-wavelength division multiplexing multi-source agreement(CW-WDM MSA)specifications.The proposed DFB laser array is flip-chip bonded to a thin-film circuit with an aluminum nitride(AlN)submount to reduce the thermal resistance and enhance the output power.Compared to the p-side-up structure,the flip-chip bonding design significantly reduces junction temperature by 28%and increases maximum output power by approximately 20%.This design effectively lowers the thermal resistance of the chip and enhances its heat dissipation properties.At a bias current of 110 mA,the laser demonstrates wavelength deviations below 1.579 GHz and side-mode suppression ratios above 50 dB.The far-field divergence is measured at 25.8°×30.1°,and the Lorentzian linewidth is 3.28 MHz.Increasing the bias current to250 mA results in a laser output power exceeding 80 mW.Furthermore,the relative intensity noise(RIN)for all 8 channels is below-135.3 d B/Hz.The proposed flip-chip bonded 8-channel high-power DFB laser array demonstrates uniform wavelength spacing,high output power,and stable single longitudinal mode performance,making it a promising candidate for multiple wavelength laser sources in optical I/O technology.展开更多
Conventional GaN-based flip-chip light-emitting diodes （CFC-LEDs） use Au bumps to contact the LED chip and Si submount, however the contact area is constrained by the number of Au bumps, limiting the heat dissipatio...Conventional GaN-based flip-chip light-emitting diodes （CFC-LEDs） use Au bumps to contact the LED chip and Si submount, however the contact area is constrained by the number of Au bumps, limiting the heat dissipation performance. This paper presents a flat surface high power GaN-based flip-chip light emitting diode （SFC-LED）, which can greatly improve the heat dissipation performance of the device. In order to understand the thermal performance of the SFC-LED thoroughly, a 3-D finite element model （FEM） is developed, and ANSYS is used to simulate the thermal performance. The temperature distributions of the SFC-LED and the CFC-LED are shown in this article, and the junction temperature simulation values of the SFC-LED and the CFC-LED are 112.80 ℃ and 122.97℃C, respectively. Simulation results prove that the junction temperature of the new structure is 10.17 ℃ lower than that of the conventional structure. Even if the CFC-LED has 24 Au bumps, the thermal resistance of the new structure is still far less than that of the conventional structure. The SFC-LED has a better thermal property.展开更多
We demonstrate a novel method for indium bump fabrication on a small CMOS circuit chip that is to be flip-chip bonded with a GaAs/A1GaAs multiple quantum well spatial light modulator. A chip holder with a via hole is ...We demonstrate a novel method for indium bump fabrication on a small CMOS circuit chip that is to be flip-chip bonded with a GaAs/A1GaAs multiple quantum well spatial light modulator. A chip holder with a via hole is used to coat the photoresist for indium bump lift-off. The 1000 μm-wide photoresist edge bead around the circuit chip can be reduced to less than 500 μm, which ensures the integrity of the indium bump array. 64 - 64 indium arrays with 20 μm-high, 30 μm-diameter bumps are successfully formed on a 5 - 6.5 mm^2 CMOS chip.展开更多
GaN based MQW epitaxial layers were grown on Si （111） substrate by MOCVD using AIN as the buffer layer. High light extraction LEDs were prepared by substrate transferring technology in combination with thin-film and...GaN based MQW epitaxial layers were grown on Si （111） substrate by MOCVD using AIN as the buffer layer. High light extraction LEDs were prepared by substrate transferring technology in combination with thin-film and flip-chip design. The blue and white 1.1 × 1.1 mm2 LED lamps are measured. The optical powers and external quantum efficiency for silicone encapsulated blue lamp are 546 mW, and 50.3% at forward current of 350 mA, while the photometric light output for a white lamp packaged with standard YAG phosphor is 120.1 lm.展开更多
The light extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes （FS- FCLEDs） using two-step roughening methods is investigated. The output power of LEDs fabricated by using one-step and tw...The light extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes （FS- FCLEDs） using two-step roughening methods is investigated. The output power of LEDs fabricated by using one-step and two-step roughening methods are compared. The results indicate that two-step roughening meth- ods show more potential for light extraction. Compared with flat FS-FCLEDs, the output power of FS-FCLEDs with a nanotextured hemisphere surface shows an enhancement of 90.7%.展开更多
基金supported by the Ministry of Commerce, Industry and Energy (MOCIE) of Korea (10031777)
文摘A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency identification(RFID) inlay. The optimization condition for flip-chip bonding was determined from the behavior of bonding strength. Under the optimized condition, the shear strength for the antenna printed with paste-type Ag ink was larger than that for Cu antenna. Furthermore, an identification distance was varied from the antenna materials. Comparing with the Ag antenna pattern, the as-bonded die on Cu antenna showed a larger distance of identification. However, the long-term reliability of inlay using the Cu antenna was decreased significantly as a function of aging time at room temperature because of the bended shape of Cu antenna formed during the flip-chip bonding process.
文摘High-power and high-reliability GaN/InGaN flip-chip light-emitting diodes （FCLEDs） have been demonstrated by employing a flip-chip design, and its fabrication process is developed. FCLED is composed of a LED die and a submount which is integrated with circuits to protect the LED from electrostatic discharge （ESD） damage. The LED die is flip-chip soldered to the submount, and light is extracted through the transparent sapphire substrate instead of an absorbing Ni/Au contact layer as in conventional GaN/InGaN LED epitaxial designs. The optical and electrical characteristics of the FCLED are presented. According to ESD IEC61000-4-2 standard （human body model）, the FCLEDs tolerated at least 10 kV ESD shock have ten times more capacity than conventional GaN/InGaN LEDs. It is shown that the light output from the FCLEDs at forward current 350mA with a forward voltage of 3.3 V is 144.68 mW, and 236.59 mW at 1.0A of forward current. With employing an optimized contact scheme the FCLEDs can easily operate up to 1.0A without significant power degradation or failure. The li.fe test of FCLEDs is performed at forward current of 200 mA at room temperature. The degradation of the light output power is no more than 9% after 1010.75 h of life test, indicating the excellent reliability. FCLEDs can be used in practice where high power and high reliability are necessary, and allow designs with a reduced number of LEDs.
基金Supported by the National Basic Research Program of China under Grant No 2012CB933501the National Natural Science Foundation of China under Grant Nos 61307033,61274070,61137003 and 61321063
文摘A single mode hybrid Ⅲ-Ⅴ/silicon on-chip laser based on the flip-chip bonding technology for on-chip optical interconnection is demonstrated. A single mode Fabry-Perot laser structure with micro-structures on an InP ridge waveguide is designed and fabricated on an InP/AIGaInAs multiple quantum well epitaxial layer structure wafer by using i-line lithography. Then, a silicon waveguide platform including a laser mounting stage is designed and fabricated on a silicon-on-insulator substrate. The single mode laser is flip-chip bonded on the laser mounting stage. The lasing light is butt-coupling to the silicon waveguide. The laser power output from a silicon waveguide is 1.3roW, and the threshold is 37mA at room temperature and continuous wave operation.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0400901 and2016YFB0400804the Key Laboratory of Infrared Imaging Materials and Detectors of Shanghai Institute of Technical Physics of Chinese Academy of Sciences under Grant NoⅡMDKFJJ-15-07+1 种基金the National Natural Science Foundation of China under Grant Nos 61675079,11574166 and 61377034the China Postdoctoral Foundation under Grant No 2016M602287
文摘High-reflectivity Al-based n-electrode is used to enhance the luminescence properties of InGaN-based 395nm flip-chip near-ultraviolet （UV） light-emitting diodes. The Al-only metal layer could form the Ohmic contact on the plasma etched n-GaN by means of chemical pre-treatment, with the lowest specific contact resistance of 2.211 × 10^-5 Ω. cm2. The AI n-electrodes enhance light output power of the 395 nm flip-chip near-UV light-emitting diodes by more than 33% compared with the Ti/AI n-electrodes. Meanwhile, the electrical characteristics of these chips with two types of n-electrodes do not show any significant discrepancy. The near-field light distribution measurement of packaged chips confirms that the enhanced luminescence is ascribed to the high refleetivity of the Al electrodes in the UV region. After the accelerated aging test for over 1000 h, the luminous degradation of the packaged chips with Al n-electrodes is less than 3%, which proves the reliability of these chips with the Al-based electrodes. Our approach shows a simplified design and fabrication of high-refleetivity n-electrode for flip-chip near-UV light emitting diodes.
基金supported by the National Natural Science Foundation of China(No.62404098)the Natural Science Foundation of Jiangsu Province of China(No.BK20241196)the National Key Research and Development Program of China(Nos.2023YFB2806400,2021YFB2801902,and 2018YFB2201801)。
文摘In this paper,we proposed and experimentally demonstrated an 8-channel O-band distributed feedback(DFB)laser array with highly uniform 400 GHz spacing and high output power for optical input/output(I/O)technology.The grating phase is precisely controlled,and an equivalentπphase shift is implemented in the laser cavity via the reconstruction equivalent chirp(REC)technology.Anti-reflection(AR)and high-reflection(HR)films are coated on the front and rear facets,respectively,to enhance output power.The equivalentπphase shift is strategically placed near the HR film facet to improve the yield of the single longitudinal mode.Operating with a 400 GHz wavelength spacing,the proposed DFB laser array meets the continuous wave-wavelength division multiplexing multi-source agreement(CW-WDM MSA)specifications.The proposed DFB laser array is flip-chip bonded to a thin-film circuit with an aluminum nitride(AlN)submount to reduce the thermal resistance and enhance the output power.Compared to the p-side-up structure,the flip-chip bonding design significantly reduces junction temperature by 28%and increases maximum output power by approximately 20%.This design effectively lowers the thermal resistance of the chip and enhances its heat dissipation properties.At a bias current of 110 mA,the laser demonstrates wavelength deviations below 1.579 GHz and side-mode suppression ratios above 50 dB.The far-field divergence is measured at 25.8°×30.1°,and the Lorentzian linewidth is 3.28 MHz.Increasing the bias current to250 mA results in a laser output power exceeding 80 mW.Furthermore,the relative intensity noise(RIN)for all 8 channels is below-135.3 d B/Hz.The proposed flip-chip bonded 8-channel high-power DFB laser array demonstrates uniform wavelength spacing,high output power,and stable single longitudinal mode performance,making it a promising candidate for multiple wavelength laser sources in optical I/O technology.
文摘Conventional GaN-based flip-chip light-emitting diodes （CFC-LEDs） use Au bumps to contact the LED chip and Si submount, however the contact area is constrained by the number of Au bumps, limiting the heat dissipation performance. This paper presents a flat surface high power GaN-based flip-chip light emitting diode （SFC-LED）, which can greatly improve the heat dissipation performance of the device. In order to understand the thermal performance of the SFC-LED thoroughly, a 3-D finite element model （FEM） is developed, and ANSYS is used to simulate the thermal performance. The temperature distributions of the SFC-LED and the CFC-LED are shown in this article, and the junction temperature simulation values of the SFC-LED and the CFC-LED are 112.80 ℃ and 122.97℃C, respectively. Simulation results prove that the junction temperature of the new structure is 10.17 ℃ lower than that of the conventional structure. Even if the CFC-LED has 24 Au bumps, the thermal resistance of the new structure is still far less than that of the conventional structure. The SFC-LED has a better thermal property.
文摘We demonstrate a novel method for indium bump fabrication on a small CMOS circuit chip that is to be flip-chip bonded with a GaAs/A1GaAs multiple quantum well spatial light modulator. A chip holder with a via hole is used to coat the photoresist for indium bump lift-off. The 1000 μm-wide photoresist edge bead around the circuit chip can be reduced to less than 500 μm, which ensures the integrity of the indium bump array. 64 - 64 indium arrays with 20 μm-high, 30 μm-diameter bumps are successfully formed on a 5 - 6.5 mm^2 CMOS chip.
文摘GaN based MQW epitaxial layers were grown on Si （111） substrate by MOCVD using AIN as the buffer layer. High light extraction LEDs were prepared by substrate transferring technology in combination with thin-film and flip-chip design. The blue and white 1.1 × 1.1 mm2 LED lamps are measured. The optical powers and external quantum efficiency for silicone encapsulated blue lamp are 546 mW, and 50.3% at forward current of 350 mA, while the photometric light output for a white lamp packaged with standard YAG phosphor is 120.1 lm.
基金supported by the National Natural Science Foundation of China(Nos.61274040,61274008)the National Basic Research Program of China(No.2011CB301902)the National High Technology Program of China(No.2011AA03A103)
文摘The light extraction enhancement of freestanding GaN-based flip-chip light-emitting diodes （FS- FCLEDs） using two-step roughening methods is investigated. The output power of LEDs fabricated by using one-step and two-step roughening methods are compared. The results indicate that two-step roughening meth- ods show more potential for light extraction. Compared with flat FS-FCLEDs, the output power of FS-FCLEDs with a nanotextured hemisphere surface shows an enhancement of 90.7%.
