Since its discovery three years ago, a process enabling extreme superconformal deposition of gold... more Since its discovery three years ago, a process enabling extreme superconformal deposition of gold in recessed features has been advanced to achieve void-free filling of progressively more varied and challenging features and patterned substrates for application in X-ray imaging. During the past year in particular, void-free filling in vias, trenches with aspect ratio (height/width) exceeding 60, trenches more than 300 mm deep, fractal patterns of spatially varying depth and fully patterned 100 mm wafers for all the aforementioned were demonstrated for the first time. Examples are shown in the included figure. The process and mechanism differ substantially from processes for superconformal copper filling of nanometer size damascene on-chip trenches and vias as well as micrometer size through silicon vias and even larger microvias used to connect semiconductor chips in the microelectronics industry. The bottom-up deposition can be initiated using a wide range of processing conditions s...
With the anticipated effects of global climate change upon us, induced by egregious CO2 emissions... more With the anticipated effects of global climate change upon us, induced by egregious CO2 emissions, it is imperative to implement technologies to close the carbon cycle. One potential technique to do this is storing the energy from intermittent sources (e.g. solar, wind, hydro) in the form of chemical bonds, such as the electrochemical reduction of CO2. By reducing CO2 to energetically and chemically useful products of CO2 (i.e. CO and C2H4) we can both reduce reliance on fossil fuels and mitigate atmospheric CO2 levels. However, controlling the selectivity towards which particular product is formed and preventing the parasitic hydrogen evolution reaction (HER) is a crucial challenge that must be overcome.1 Exploring fundamental mechanisms and new catalyst materials to overcome this challenge, can be skewed due to the low diffusivity (≈2x10-9 m2/s)2 of CO2 in the liquid phase causing inefficient utilization of catalyst active sites. Unlike the oxygen reduction reaction, use of a rota...
Silicon photoanodes patterned with thin-film Ni catalyst islands exhibited stable sunlight-driven... more Silicon photoanodes patterned with thin-film Ni catalyst islands exhibited stable sunlight-driven O2evolution for over 240 h of continuous operation in 1.0 M KOH.
This study describes and demonstrates a systematic approach for deconvoluting the influences of 3... more This study describes and demonstrates a systematic approach for deconvoluting the influences of 3D structure on photoelectrode performance.
This work demonstrates void-free nickel filling of 56 μm tall, annular Through Silicon Vias (TSVs... more This work demonstrates void-free nickel filling of 56 μm tall, annular Through Silicon Vias (TSVs) using a mechanism that couples suppression breakdown and surface topography to achieve controlled superconformal, void-free deposition. The chemistry, a Watts electrolyte containing a dilute suppressing additive, and processes are fully detailed. The impact of deposition potential and additive concentration on the filling of the patterned features is presented. Voltammetric measurements on planar substrates, including the impact of rotation rate and suppressor concentration on the rate of metal deposition and potential of suppression breakdown, are used to quantify the interplay between metal deposition and suppressor adsorption. The derived kinetics are then used to quantitatively predict the observed bottom-up filling in the TSVs using the S-shaped negative differential resistance (S-NDR) mechanism for superconformal deposition; the predictions capture the experimental observations. ...
Since its discovery three years ago, a process enabling extreme superconformal deposition of gold... more Since its discovery three years ago, a process enabling extreme superconformal deposition of gold in recessed features has been advanced to achieve void-free filling of progressively more varied and challenging features and patterned substrates for application in X-ray imaging. During the past year in particular, void-free filling in vias, trenches with aspect ratio (height/width) exceeding 60, trenches more than 300 mm deep, fractal patterns of spatially varying depth and fully patterned 100 mm wafers for all the aforementioned were demonstrated for the first time. Examples are shown in the included figure. The process and mechanism differ substantially from processes for superconformal copper filling of nanometer size damascene on-chip trenches and vias as well as micrometer size through silicon vias and even larger microvias used to connect semiconductor chips in the microelectronics industry. The bottom-up deposition can be initiated using a wide range of processing conditions s...
With the anticipated effects of global climate change upon us, induced by egregious CO2 emissions... more With the anticipated effects of global climate change upon us, induced by egregious CO2 emissions, it is imperative to implement technologies to close the carbon cycle. One potential technique to do this is storing the energy from intermittent sources (e.g. solar, wind, hydro) in the form of chemical bonds, such as the electrochemical reduction of CO2. By reducing CO2 to energetically and chemically useful products of CO2 (i.e. CO and C2H4) we can both reduce reliance on fossil fuels and mitigate atmospheric CO2 levels. However, controlling the selectivity towards which particular product is formed and preventing the parasitic hydrogen evolution reaction (HER) is a crucial challenge that must be overcome.1 Exploring fundamental mechanisms and new catalyst materials to overcome this challenge, can be skewed due to the low diffusivity (≈2x10-9 m2/s)2 of CO2 in the liquid phase causing inefficient utilization of catalyst active sites. Unlike the oxygen reduction reaction, use of a rota...
Silicon photoanodes patterned with thin-film Ni catalyst islands exhibited stable sunlight-driven... more Silicon photoanodes patterned with thin-film Ni catalyst islands exhibited stable sunlight-driven O2evolution for over 240 h of continuous operation in 1.0 M KOH.
This study describes and demonstrates a systematic approach for deconvoluting the influences of 3... more This study describes and demonstrates a systematic approach for deconvoluting the influences of 3D structure on photoelectrode performance.
This work demonstrates void-free nickel filling of 56 μm tall, annular Through Silicon Vias (TSVs... more This work demonstrates void-free nickel filling of 56 μm tall, annular Through Silicon Vias (TSVs) using a mechanism that couples suppression breakdown and surface topography to achieve controlled superconformal, void-free deposition. The chemistry, a Watts electrolyte containing a dilute suppressing additive, and processes are fully detailed. The impact of deposition potential and additive concentration on the filling of the patterned features is presented. Voltammetric measurements on planar substrates, including the impact of rotation rate and suppressor concentration on the rate of metal deposition and potential of suppression breakdown, are used to quantify the interplay between metal deposition and suppressor adsorption. The derived kinetics are then used to quantitatively predict the observed bottom-up filling in the TSVs using the S-shaped negative differential resistance (S-NDR) mechanism for superconformal deposition; the predictions capture the experimental observations. ...
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