O-Band Subwavelength Grating Filters in a Monolithic Photonics Technology

The data communications industry has begun transitioning from electrical to optical interconnects in datacenters in order to overcome performance bottlenecks and meet consumer needs. To mitigate the costs associated with this change and achieve performance for 5G and beyond, it is crucial to explore advanced photonic devices that can enable high-bandwidth interconnects via wavelength-division multiplexing (WDM) in photonic integrated circuits. Subwavelength grating (SWG) filters have shown great promise for WDM applications. However, the small feature sizes necessary to implement these structures have prohibited them from penetrating into industrial applications. To explore the manufacturability and performance of SWG filters in an industrial setting, we fabricate and characterize O-band subwavelength grating filters using the monolithic photonics technology at GLOBALFOUNDRIES (GF). We demonstrate a low drop channel loss of -1.2 dB with a flat-top response, a high extinction ratio of -30 dB, a 3 dB channel width of 5 nm and single-source thermal tunability without shape distortion. This filter structure was designed using elements from the product design kit provided by GF and functions in a compact footprint of 0.002 mm2 with a minimum feature size of 150 nm.Comment: 4 pages, 3 figure

Investigation of the Fundamental Reliability Unit for Cu Dual-Damascene Metallization

An investigation has been carried out to determine the fundamental reliability unit of copper dual-damascene metallization. Electromigration experiments have been carried out on straight via-to-via interconnects in the lower metal (M1) and the upper metal (M2), and in a simple interconnect tree structure consisting of straight via-to-via line with an extra via in the middle of the line (a "dotted-I"). Multiple failure mechanisms have been observed during electromigration testing of via-to-via Cu interconnects. The failure times of the M2 test structures are significantly longer than that of identical M1 structures. It is proposed that this asymmetry is the result of a difference in the location of void formation and growth, which is believed to be related to the ease of electromigration-induced void nucleation and growth at the Cu/Si₃N₄ interface. However, voids were also detected in the vias instead of in the Cu lines for some cases of early failure of the test lines. These early failures are suspected to be related to the integrity and reliability of the Cu via. Different magnitudes and directions of electrical current were applied independently in two segments of the interconnect tree structure. As with Al-based interconnects, the reliability of a segment in this tree strongly depends on the stress conditions of the connected segment. Beyond this, there are important differences in the results obtained under similar test conditions for Al-based and Cu-based interconnect trees. These differences are thought to be associated with variations in the architectural schemes of the two metallizations. The absence of a conducting electromigration-resistant overlayer in Cu technology allows smaller voids to cause failure in Cu compared to Al. Moreover, the Si₃N₄ overlayer that serves as an interlevel diffusion barrier provides sites for easy nucleation of voids and also provides a high diffusivity path for electromigration. The results reported here suggest that while segments are not the fundamental reliability unit for circuit-level reliability assessments for Al or Cu, vias, rather than trees, might be the appropriate fundamental units for the assessment of Cu reliability.Singapore-MIT Alliance (SMA

Distress Tolerance as a Potential Target for Change: The Relationship Between Distress Tolerance, Craving, and Alcohol Consumption in a Lab-based Experiment

Distress tolerance (DT) has recently been studied as a potential catalyst for the development ofalcohol use disorder (AUD). Research exploring the relationship between DT and craving is limited and has primarily focused on nicotine craving. Furthermore, there are no current studies examining the relationship between DT and alcohol consumption. This study was designed to fill this gap in the literature, which may shed light on a potentially important target for alcohol use treatment. Additionally, the role of mindfulness was explored in the context of the relationship between DT and alcohol craving and consumption, with the intention of expanding on the existing literature demonstrating the utility of mindfulness-based interventions for AUD. This study consisted of 71 participants age 21-35, recruited as part of a larger research study. Trait DT, trait mindfulness, and an initial craving rating were assessed at baseline. Individuals were then given a negative mood induction task. After the mood induction, individuals were given measures of momentary distress intolerance and craving. Next, participants were given an alcohol taste-task to measure ad libitum alcohol consumption, after which they completed a measure of state mindfulness. Individuals with higher momentary distress intolerance after the mood induction had a greater increase in craving from pre- to post- mood induction; there was no significant relationship between trait DT and craving. Trait DT and momentary distress intolerance were not predictive of alcohol consumption in this study. Additionally, mindfulness measures did not moderate the relationship between DT measures and alcohol craving or consumption. Further research is needed to better understand the relationship between DT and alcohol craving and alcohol consumption, as well as the potentially important role of mindfulness in the treatment of AUD