Fig 4 - uploaded by Peter Ressel
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SEM cross section of Au/Sn solder joint: (a) under the chip, where excess gold causes-phase growth. (b) Unmetallized area under the chip and beside the chip, where the eutectic preserves during soldering.
Source publication
High power diode lasers become more and more important to industrial and medical applications. In contrast to low power applications long cavity lasers of laser bars are used in this field and mounting influences considerably laser performance and life time. In this paper we focus on the solder metallurgy and stress-induced laser behavior after mou...
Citations
... powdered solder dispersed in a viscous flux paste in preform and paste methods [44,53,56]. Direct film deposition approaches, on the other hand, entails depositing films of solder material in a tightly controlled environment, e.g., sputtering/evaporation and electrochemical plating (ECP) [17,49,[56][57][58][59]. In sputtering/evaporation method, chamber with controlled parameters is used via self-sustaining plasma or electron beam for solder deposition. ...
... Samples that pass the test are either sent for product assembly packaging or sent for lifetests. Lifetest may be carried out by first dividing the samples into three groups subjected to different conditions (e.g., 100, 150, 200°C; and 300, 400, 500mA) to for statistical comparison in order to retrieve the aging factor [58]. For assembly component qualification plan, laser/SOA samples may be subjected to ESD tests while PIC sampleswhich has metallization layers, bond, wirebond, and wirebonding padsmay be subjected to back-end of line (BEOL) tests (e.g., SM and EM tests). ...
Silicon photonic integrated circuit (PIC) builds on the demand for a low cost PIC approach from established silicon-based manufacturing infrastructure traditionally built for electronics. Besides its natural abundance, silicon has desirable properties such as optically low loss (at certain critical wavelengths), and small form factor to enable high density scaled-up optical on-chip circuitry. However, given that silicon is an indirect bandgap material, the platform is typically integrated with other direct bandgap (e.g., III-V semiconductor) platforms for on-chip light source. An effective solution to integrating light source onto silicon photonics platform is integral to a practical scaled-up and full-fledged integrated photonics implementation. Here, we discuss the integration solutions, and present our foundry's perspective toward realizing it.
... So here, wider stripes (395 µm vs 186 µm) are chosen for the ETAS bars for improved performance. Also, in order to avoid ring oscillations, the contacts of the emitters in the ETAS bars are sub-structured into 5 µm wide sub-stripes at 10 µm period [14]. Emitters in both ASLOC and ETAS bars are defined by ion implantation (using 4 He + ions) of the contact layer. ...
GaAs-based, highly-efficient, kW-class, 1-cm laser bars with high peak power
P
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">opt</sub>
and improved beam quality in quasi-continuous-wave mode are presented. The use of an extreme-triple-asymmetric (ETAS) epitaxial layer structure diminishes power saturation of high-power bars at high driving current. The resulting ETAS bars with 4 mm cavity produce a record 1.9 kW peak power, limited by available current supply, with a maximum power conversion efficiency
η
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</sub>
= 67% at
T
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HS</sub>
= 25 °C heat-sink temperature. Both
P
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">opt</sub>
and
η
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</sub>
have been increased further by operating the bars at
T
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HS</sub>
= −70 °C. Sub-zero operation raises the
P
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">opt</sub>
to 2.3 kW and the maximum
η
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</sub>
to 74%. A second configuration of ETAS bars with optimized lateral layout is further realized to obtain narrow lateral beam divergence
θ
up to 2 kA driving current, without sacrificing
P
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">opt</sub>
and
η
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</sub>
. A 2–3° lower
θ
(95% power level) is observed over a wide operating range at room temperature. A high degree of polarization is also maintained across the whole operatingrange.
... Boron nitride (BN) has three isostructural forms known as amorphous, hexagonal, and cubic similar to carbon. Due to its higher thermal conductivity than copper, it is used as a heatsink in electronics applications [61]. ...
Additive manufacturing (AM) has become a versatile and diversified technology that has made a huge difference in how things are being manufactured. Substantial growth has been observed in the development of ceramic materials for AM processes. However, ceramic parts manufactured by AM methods often exhibit deficiencies in mechanical properties and performance. Recent research developments have included improvement of performance and mechanical properties by introducing a material preparation process and additional post-processing techniques to improve the fabrication process. This paper contemplates and reviews the advancements made in AM techniques to fabricate high-performance ceramic (HPC) materials, also known as advanced ceramics. AM processes are classified as per ASTM standards and the technologies implemented are sub-listed. The principles, mechanical properties, advantages, disadvantages, applications, and limitations of each technology are described in detail.
... In early work, diode laser mini arrays with 1.64 mm aperture and 4 mm resonator length that operated with P opt = 100 W were used to construct stacks of 12 diode lasers. The emission from single stacks was optically combined and coupled into a fiber with 1.2 mm core and NA = 0.22, to produce pump modules that delivered a peak power from fiber of 1 kW (1 J pulse energy in a pulse of 1 ms duration) at a duty cycle of 10% (f = 100 Hz) [23]. With the help of these early diode laser pump modules, the MBI was able to develop several laser systems consisting of different amplifiers based on Yb:YAG thin-disk technology [24], for example designed as driver for a laser-plasma based X-ray laser [25]. ...
The latest generation of high-energy-class pulsed laser facilities, under construction or planned, such as EuPRAXIA, require reliable pump sources with high power (many kW), brightness (>1 MW/cm2/sr) and electro-optical conversion efficiency (>50%). These new facilities will be operated at high repetition rates (around 100 Hz) and only diode lasers are capable of delivering the necessary performance. Commercial (quasi-continuous wave, QCW) diode laser pulse-pump sources are, however, constructed as low-cost passively cooled stacked arrays that are limited either in brightness, efficiency or repetition rate. Commercial continuous wave diode laser pumps constructed using microchannel coolers (as used in high-value industrial machine tools) can fulfil all requirements, but are typically not preferred, due to their cost and complexity and the challenges of preventing cooler degradation. A custom solution is shown here to fill this gap, using advanced diode lasers in a novel passive side-cooling geometry to realize 100 … 200 Hz pump modules (10%–20% duty cycle) that emit peak power of 6 kW at wavelength = 940 nm. The latest performance of these modules is summarized and compared to literature. We show that a brightness >1 MW/cm2/sr can be efficiently delivered across a wide range of laser pulse conditions with 10% duty cycle (pulse width: 100 µs … 100 ms … cw, repetition rate up to 1 kHz). Furthermore, we describe how these pumps have been used to construct and reliably operate (>109 pulses without degradation) in high-energy-class regenerative and ring amplifiers at the Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI). We also show first results on 100 Hz pumping of cryogenically cooled solid-state Yb:YAG slab amplifiers, as anticipated for use in the EuPRAXIA laser, and note that peak temperature is disproportionately increased, indicating that improved cooling and more detailed studies are needed.
... During the past two decades, thin film deposition of BN has attracted interested in applications as high-temperature dielectrics, electron field emitters, coatings for tribological applications and interfacial layers for optoelectronic devices and electrically insulating layers [3]. Nowadays, BN coatings have been successfully used in the industrial cutting inserts, heat sinks, lower friction coefficient surface manufacturing, rollers, bearings, high-temperature crucibles, masks for the X-ray lithography, and sodium barriers in microelectronic [4][5][6][7][8][9]. The BN thin film is only one option for the high temperature application instead of the diamond like carbon -(DLC) and DLC coating. ...
The BN thin film is only one option for the high temperature application instead of the diamond like carbon coatings. Cubic form BN thin film is hard. The friction coefficient is also very low in hexagonal form. An alternative method for the BN coating is RF magnetron sputtering system. In this paper, BN thin films were deposited by RF magnetron sputtering. The film thickness changed in the range of 20–120 nm. In XRD patterns, 2 theta values of 29.48° (143), 44.61° (400) which exhibits the phase of the e-BN and 41.86° (100), 39.80° (010) indicates the phase of h-BN crystals. The smallest crystallites sizes were calculated as to be 12 nm and biggest crystallites sizes ere calculated as to be 66 nm. A strong Raman peak at approximately 1086 cm⁻¹ were measured, correspond the cubic phase of BN. According to the Raman spectra, pure c-BN thin films were deposited.
... For instance, Wada et al. [4e6] demonstrated the excellent thermal stability of Au-20 wt%SnjPt metallization system over a temperature range relevant to chip bonding and device service by studying the effective interdiffusion coefficient and the activation energy. The investigations initiated by Pittroff et al. [15], Klein et al. [20], Katz et al. [10], and Ivey [14] revealed that Pt was an acceptable barrier layer for bonding optoelectronic devices onto submounts. However, Lee et al. [12] and Park [16] argued that the short surface local freezing time (9 s) of Pt/Ti/Au-Sn metallization system [12] and extensive interaction between Sn and Pt [10,16] might increase the melting temperature of the solder and thus lead to mechanical deterioration of the bonded assembly. ...
The Calphad method has been employed to reassess the thermodynamic description of the Au-Pt-Sn ternary system by remodeling the ternary compound and the solubility of the third elements in relevant binary compounds. A set of consistent parameters was obtained with reproducing most of the experimental results. The microstructures of as-soldered and aged Au-20 wt%Sn|Pt reaction couples were characterized by using scanning electron microscopy with energy-dispersive X-ray microanalysis (EDS), as well as scanning transmission electron microscopy with EDS. During soldering, the (Au1-x,Ptx)Sn (0 ≤ x ≤ 0.5) intermetallic compound layer was formed at solder/Pt interface and evolved with prolonged bonding time. When the as-soldered samples were subsequently annealed at 150 °C for up to 4600 h, only one interfacial intermetallic compound (Au1-x,Ptx)Sn was observed. The average thickness of the (Au1-x,Ptx)Sn layer was reached ∼ 3.3 μm already after 100 h of aging and remained practically constant with the progress of the aging process. When samples were isothermally aged for 6848 h, in addition to the thick (Au1-x,Ptx)Sn interfacial layer, a thin (no more than 100 nm) PtSn layer was observed at the interface of (Au1-x,Ptx)Sn/Pt. These results indicate that the Au-20 wt%Sn|Pt interconnections are thermally stabile at 150 °C. The interfacial reaction mechanism of Au-20 wt%Sn|Pt at 150 °C has been proposed by combining experimental results with the basic thermodynamic considerations. Moreover, the microstructure of Au-20 wt%Sn|Pt was compared with those of Au-20 wt%Sn|Ni and Au-20 wt%Sn|Cu. The advantages and disadvantages of Au-20 wt%Sn solder on Ni, Cu and Pt contact metallizations were discussed.
... Among the III semiconductors, boron nitride (BN) stands out, due to its excellent physical, mechanical, and thermal properties, such as high-temperature stability, chemical inertia, a high degree of hardness, a low coefficient of thermal expansion, a high melting point, and high thermal conductivity [6][7][8][9]. BN has a broad range of potential applications, such as in high-temperature ceramic materials that can withstand an extremely harsh environment, radio frequency and high-frequency high-power laser diodes, light-emitting diodes operating in the ultraviolet region, solar detectors, field-effect transistors, and high electron mobility transistors [10][11][12][13][14][15]. Owing to its variable bonding character, BN can exist in different crystallographic phases, such as zincblende, cubic boron nitride (c-BN) [16][17][18], wurtzite (w) boron nitride (w-BN) [17,19,20], hexagonal (h) boron nitride (h-BN) [4,5], and rhombohedral (r) boron nitride (r-BN) [1,2]. ...
... These properties make this material a good candidate for high reliability applications in extreme environments [3]. Among potential applications, the eutectic 80Au/20Sn solder alloy is particularly attractive for use in high power electronics and optoelectronics as a hermetic sealing and die attachment material due to its excellent high temperature performance, mechanical strength, electrical and thermal conductivity, and ability for fluxless soldering [4][5][6][7][8][9][10]. The manufacturing process for such applications has been investigated extensively, with emphasis on the bonding quality, metallurgical interactions, and formation of a Au-Sn solder bump [11][12][13][14][15]. Rodriguez et al. [3] studied the thermal stability of Au-Sn bonding for high temperature applications. ...
The eutectic 80Au/20Sn solder alloy is widely used in high power electronics and optoelectronics packaging. In this study, low cycle fatigue behavior of a eutectic 80Au/20Sn solder alloy is reported. The 80Au/20Sn solder shows a quasi-static fracture characteristic at high strain rates, and then gradually transforms from a transgranular fracture (dominated by fatigue damage) to intergranular fracture (dominated by creep damage) at low strain rates with increasing temperature. Coffin-Manson and Morrow models are proposed to evaluate the low cycle fatigue behavior of the 80Au/20Sn solder. Besides, the 80Au/20Sn solder has enhanced fatigue resistance compared to the 63Sn/37Pb solder.
... For applications with less than 60 W thermally dissipated power per laser bar, conductively cooled heatsinks are preferred, which are normally based on a heat spreader, such as microchannel cooler (MCC), and jet cooler packaging technologies (135)(136)(137)(138). MCC is commonly made from multiple layers of copper. The laser diode bar is often soldered directly to the cooler (139)(140)(141). CTE plays an important role in determining the overall performance and degradation time of the diode laser product. ...
In recent years, the packaging technologies of advanced optoelectronics devices and systems have evolved rapidly to meet the fast-growing industry of optoelectronics. However, packaging expense still accounts for a major portion of the overall cost of optoelectronics devices and systems. With the driving trend of higher power, smaller size, and higher reliability, many advanced packaging technologies are emerging. In this article, we present a comprehensive introduction of packaging design rules, advanced packaging materials, and packaging processes. Specific examples with state-of-art packaging methodologies are given for some typical devices, including high-power, light-emitting diodes; high-power semiconductor lasers; liquid crystal displays; and fiber-related optical devices. Insights on the technological development trend and philosophy are also discussed for advanced packaging of optoelectronic devices.
... Diamond has a six-times larger thermal conductivity compared to the expansion matched CuW, but the coefficient of thermal expansion CTE between diamond (1.6 × 10 −6 K −1 ) is smaller compared to GaAs (6.5 × 10 −6 K −1 ). The CVD diamond was previously coated with AuSn to form ζ -phase during soldering [17]. To avoid a negative impact of this mismatch on reliability, the heat sink metallization together and the metallization of the devices had to be adapted. ...
Reliability tests for highly efficient high-power 650 nm broad area diode lasers will be presented. The devices have a 5 nm thick single GaInP quantum well as an active layer, which is embedded in AlGaInP waveguide layers and n-AlInP and p-AlGaAs cladding layers. The devices with a stripe width of 100 µm and a cavity length of 1.5 mm were soldered on diamond submounts and mounted on standard C-mounts for an efficient heat removal. The test was performed at a temperature of 15 °C over a first period of 10 000 h at 1.1 W followed by a second period of 10 000 h at 1.2 W. Based on the aging test and assuming a 60% confidence level, the lower limit of the mean time to failure of 87 000 h was determined for the devices.
