Browsing by Subject "Drain"

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  • Vohra, Anurag; Makkonen, Ilja; Pourtois, Geoffrey; Slotte, Jonatan; Porret, Clement; Rosseel, Erik; Khanam, Afrina; Tirrito, Matteo; Douhard, Bastien; Loo, Roger; Vandervorst, Wilfried (2020)
    This paper benchmarks various epitaxial growth schemes based on n-type group-IV materials as viable source/drain candidates for Ge nMOS devices. Si:P grown at low temperature on Ge, gives an active carrier concentration as high as 3.5 x 10(20) cm(-3) and a contact resistivity down to 7.5 x 10(-9) However, Si:P growth is highly defective due to large lattice mismatch between Si and Ge. Within the material stacks assessed, one option for Ge nMOS source/drain stressors would be to stack Si:P, deposited at contact level, on top of a selectively grown n-SiyGe1-x-ySnx at source/drain level, in line with the concept of Si passivation of n-Ge surfaces to achieve low contact resistivities as reported in literature (Martens et al. 2011 Appl. Phys. Lett., 98, 013 504). The saturation in active carrier concentration with increasing P (or As)-doping is the major bottleneck in achieving low contact resistivities for as-grown Ge or SiyGe1-x-ySnx. We focus on understanding various dopant deactivation mechanisms in P-doped Ge and Ge1-xSnx alloys. First principles simulation results suggest that P deactivation in Ge and Ge1-xSnx can be explained both by P-clustering and donor-vacancy complexes. Positron annihilation spectroscopy analysis, suggests that dopant deactivation in P-doped Ge and Ge1-xSnx is primarily due to the formation of P-n-V and SnmPn-V clusters. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
  • Tommiska, Pihla; Lonnrot, Kimmo; Raj, Rahul; Luostarinen, Teemu; Kivisaari, Riku (2019)
    BACKGROUND: A number of randomized controlled trials have shown the benefit of drain placement in the operative treatment of chronic subdural hematoma (CSDH); however, few reports have described real-life results after adoption of drain placement into clinical practice. We report the results following a change in practice at Helsinki University Hospital from no drain to subdural drain (SD) placement after burr hole craniostomy for CSDH. METHODS: We conducted a retrospective observational study of consecutive patients undergoing burr hole craniostomy for CSDH. We compared outcomes between a 6-month period when SD placement was arbitrary (Julye December 2015) and a period when SD placement for 48 hours was routine (July-December 2017). Our primary outcome of interest was recurrence of CSDH necessitating reoperation within 6 months. Patient outcomes, infections, and other complications were assessed as well. RESULTS: A total of 161 patients were included, comprising 71 (44%) in the drain group and 90 (56%) in the non-drain group. There were no significant differences in age, comorbidities, history of trauma, or use of antithrombotic agents between the 2 groups (P > 0.05 for all). Recurrence within 6 months occurred in 18% of patients in the non-drain group, compared with 6% in the drain group (odds ratio, 0.28; 95% confidence interval, 0.09-0.87; P = 0.028). There were no differences in neurologic outcomes (P = 0.72), mortality (P = 0.55), infection rate (P = 0.96), or other complications (P = 0.20). CONCLUSIONS: The change in practice from no drain to use of an SD after burr hole craniostomy for CSDH effectively reduced the 6-month recurrence rate with no effect on patient outcomes, infections, or other complications.