Analytical methodology development for Silicon rich oxide chemical physical characterization

Silicon-rich-oxide (SRO) layers and silicon nano-crystals (Si-nc) have been gaining particular attention for their optoelectronic properties. Analytical techniques as secondary ion mass spectrometry (SIMS), photo-electron spectroscopy (XPS), variable angle spectroscopy ellipsometry (VASE) and atomic force microscopy (AFM) were considered in this work as helpful ways to obtain the required characterization of these materials. SRO different films were deposited on Si wafers by plasma enhanced chemical vapor deposition (PECVD) and varying the ratio between SiH4, N2O and NH3. Then they were analyzed by SIMS and XPS, which combine the chemical physical analytical techniques requested to provide quantitative and accurate results. Besides the high precision of SIMS profiles, the accuracy of the data in SRO is marked as a difficult task, because of different matrices in different films. Therefore a fit equation for silicon SIMS depth profiles quantification in SRO is proposed. The physic-chemical data were related to VASE measurements. Furthermore the structural properties of silicon nano-crystals were investigated by AFM. The developed methodology confirms undoubtedly the Si-nc growth

Multilayer silicon rich oxy-nitride films characterization by SIMS, VASE and AFM

In this work secondary ion mass spectrometry (SIMS), variable angle spectroscopy ellipsometry (VASE) and atomic force microscopy (AFM) are used to investigate the structure, composition and morphology of multilayer SRON films. Three/four SRON sequential layers were deposited on silicon wafers by PECVD and silicon, nitrogen and oxygen content was varied by changing the N2O/SiH4 ratio. The total thickness of the resulting SRON stack is about 50nm. SIMS analyses of NCs+, OCs+, SiCs+, in MCs+ methodology are performed by a Cameca SC-ultra instrument. Depth profiles are obtained at 500eV of primary beam impact energy with sample rotation. An approximate method to obtain silicon concentration is used. Total layer thickness are obtained from both SIMS and VASE measurements. In addition, we compare the thickness of the single layers obtained from VASE with the SIMS depth profiles. A detailed analysis of films morphology is obtained by AFM. The SRON stack is sputtered by SIMS until a certain layer is exposed, which is then analyzed by AFM. The sputtered layers are then etched in HF solution to better resolve the exposed nano-crystals

Results of Arthroscopic Revision Rotator Cuff Repair for Failed Open or Arthroscopic Repair: A Prospective Multicenter Study on 100 Cases

Background: Retears after rotator cuff repair (RCR) have been associated with poor clinical results. Meaningful data regarding the role of arthroscopic revision RCR are sparse thus far. Purpose/Hypothesis: To investigate results after arthroscopic revision RCR. We hypothesized that (1) arthroscopic revision RCR would lead to improved outcomes, (2) the clinical results would be dependent on tendon integrity and (3) tear pattern, tendon involvement, and repair technique would influence clinical and structural results. Study Design: Case series; Level of evidence 4. Methods: During a 40-month period, 100 patients who underwent arthroscopic revision RCR were prospectively enrolled in this multicenter study. Outcomes were evaluated preoperatively, at 6 months (6M), and at 24 months (24M) using the Constant score (CS), the Oxford Shoulder Score (OSS), and the Subjective Shoulder Value (SSV). Tendon integrity at 2 years was analyzed using magnetic resonance imaging. A total of 13 patients (13%) were lost to follow-up, and 14 patients (14%) had a symptomatic retear before the 24M follow-up. Results: All clinical scores improved significantly during the study period (CS: preoperative, 44 +/- 16; 6M, 58 +/- 22; 24M, 69 +/- 19 points; OSS: preoperative, 27 +/- 8; 6M, 36 +/- 11; 24M, 40 +/- 9 points; SSV: preoperative, 43% +/- 18%; 6M, 66% +/- 24%; 24M, 75% +/- 22%) (P = 2, and medial cuff failure were correlated with poorer SSV scores at 2 years (P <= .047). Patients with traumatic retears had better CS and OSS scores at 2 years (P <= .039). Conclusion: Although arthroscopic revision RCR improved shoulder function, retears were frequent but usually smaller. Patients with retears, however, did not necessarily have poorer shoulder function. Patient satisfaction at 2 years was lower when primary open RCR was performed, when a subscapularis tear or osteoarthritis was present, and when the rotator cuff retear was located at the musculotendinous junction. Patients with traumatic retears showed better functional improvement after revision