Control for Advanced Semiconductor Device Manufacturing: A Case History

2018 ◽  
pp. 67-83
Author(s):  
T. Kailath ◽  
C. Schaper ◽  
Y. Cho ◽  
P. Gyugyi ◽  
S. Norman ◽  
...  
Keyword(s):  
Case History ◽  
Semiconductor Device

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

Applications of SIMS to electronic materials and devices

1992 ◽  
Vol 50 (2) ◽  
pp. 1682-1683
Author(s):  
S.F. Corcoran
Keyword(s):  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Electronic Materials ◽  
Profile Analysis ◽  
Semiconductor Industry ◽  
Small Diameter ◽  
Depth Resolution ◽  
Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

Structural and electronic properties of defects in semiconductors

1995 ◽  
Vol 53 ◽  
pp. 4-5
Author(s):  
J.L. Batstone
Keyword(s):  
Semiconductor Device ◽  
Chemical Vapor ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Extended Defects ◽  
Transmission Electron ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Metal Organic ◽  
Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

Metal Microstructures in Advanced CMOS Devices

1996 ◽  
Vol 54 ◽  
pp. 358-359
Author(s):  
L. M. Gignac ◽  
K. P. Rodbell
Keyword(s):  
Grain Boundaries ◽  
Semiconductor Device ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Metal Films ◽  
Thin Metal ◽  
Electrical Performance ◽  
Thin Metal Films ◽  
Chemical Vapor Deposited ◽  
Boundary Properties

As advanced semiconductor device features shrink, grain boundaries and interfaces become increasingly more important to the properties of thin metal films. With film thicknesses decreasing to the range of 10 nm and the corresponding features also decreasing to sub-micrometer sizes, interface and grain boundary properties become dominant. In this regime the details of the surfaces and grain boundaries dictate the interactions between film layers and the subsequent electrical properties. Therefore it is necessary to accurately characterize these materials on the proper length scale in order to first understand and then to improve the device effectiveness. In this talk we will examine the importance of microstructural characterization of thin metal films used in semiconductor devices and show how microstructure can influence the electrical performance. Specifically, we will review Co and Ti silicides for silicon contact and gate conductor applications, Ti/TiN liner films used for adhesion and diffusion barriers in chemical vapor deposited (CVD) tungsten vertical wiring (vias) and Ti/AlCu/Ti-TiN films used as planar interconnect metal lines.

Behavior of contact-silicided TFSOI gate structures

1994 ◽  
Vol 52 ◽  
pp. 860-861
Author(s):  
N. David Theodore ◽  
Juergen Foerstner ◽  
Peter Fejes
Keyword(s):  
Semiconductor Device ◽  
Series Resistance ◽  
Field Effect Transistors ◽  
Silicon Layer ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
Continuous Layer ◽  
Buried Oxide ◽  
Device Structures ◽  
Thin Silicon

As semiconductor device dimensions shrink and packing-densities rise, issues of parasitic capacitance and circuit speed become increasingly important. The use of thin-film silicon-on-insulator (TFSOI) substrates for device fabrication is being explored in order to increase switching speeds. One version of TFSOI being explored for device fabrication is SIMOX (Silicon-separation by Implanted OXygen).A buried oxide layer is created by highdose oxygen implantation into silicon wafers followed by annealing to cause coalescence of oxide regions into a continuous layer. A thin silicon layer remains above the buried oxide (~220 nm Si after additional thinning). Device structures can now be fabricated upon this thin silicon layer.Current fabrication of metal-oxidesemiconductor field-effect transistors (MOSFETs) requires formation of a polysilicon/oxide gate between source and drain regions. Contact to the source/drain and gate regions is typically made by use of TiSi2 layers followedby Al(Cu) metal lines. TiSi2 has a relatively low contact resistance and reduces the series resistance of both source/drain as well as gate regions

Misophonia: An Evidence-Based Case Report

2020 ◽  
Vol 29 (4) ◽  
pp. 685-690
Author(s):  
C. S. Vanaja ◽  
Miriam Soni Abigail
Keyword(s):  
Quality Of Life ◽  
Case Report ◽  
Case History ◽  
Pure Tone ◽  
Physiological Responses ◽  
Evidence Based ◽  
Management Option ◽  
Pure Tone Audiogram

Purpose Misophonia is a sound tolerance disorder condition in certain sounds that trigger intense emotional or physiological responses. While some persons may experience misophonia, a few patients suffer from misophonia. However, there is a dearth of literature on audiological assessment and management of persons with misophonia. The purpose of this report is to discuss the assessment of misophonia and highlight the management option that helped a patient with misophonia. Method A case study of a 26-year-old woman with the complaint of decreased tolerance to specific sounds affecting quality of life is reported. Audiological assessment differentiated misophonia from hyperacusis. Management included retraining counseling as well as desensitization and habituation therapy based on the principles described by P. J. Jastreboff and Jastreboff (2014). A misophonia questionnaire was administered at regular intervals to monitor the effectiveness of therapy. Results A detailed case history and audiological evaluations including pure-tone audiogram and Johnson Hyperacusis Index revealed the presence of misophonia. The patient benefitted from intervention, and the scores of the misophonia questionnaire indicated a decrease in the severity of the problem. Conclusions It is important to differentially diagnose misophonia and hyperacusis in persons with sound tolerance disorders. Retraining counseling as well as desensitization and habituation therapy can help patients who suffer from misophonia.

Counseling Parents at the Time of Diagnosis: Moving Toward Client-Centered Practice

2020 ◽  
pp. 1-5
Author(s):  
David Luterman
Keyword(s):  
Case History ◽  
Medical Model ◽  
Diagnostic Process ◽  
Separate Entity ◽  
Initial Examination ◽  
Personal Adjustment ◽  
Flow Of Information ◽  
Ultimate Purpose

Purpose The purpose of this article is to present a client-centered model of counseling that integrates information and personal adjustment counseling. Research has indicated that audiologists are more comfortable with counseling that is information based than with personal adjustment counseling. The prevailing model of diagnosis appears to be the medical model in which, first, a case history is taken, then testing and, finally, counseling. This model lends itself to audiologist as expert and the counseling as a separate entity based on information and advice. Further research has indicated parents retain little of the information provided in the initial examination because of their heightened emotions. This article presents a client-centered model of diagnosis in which information is provided within an emotionally safe context, enabling the parents to express their feelings and have the ability to control the flow of information. The ultimate purpose of a client-centered model is to empower parents by making them active participants in the diagnostic process rather than passive recipients. Conclusion The client-centered model has wide implications for the diagnostic process as well as for the training of students.

School-Based Speech-Language Pathologists' Adherence to Practice Guidelines for Assessment of English Learners

2020 ◽  
pp. 1-12
Author(s):  
Virginia L. Dubasik ◽  
Dubravka Svetina Valdivia
Keyword(s):  
Professional Practice ◽  
Practice Guidelines ◽  
Case History ◽  
English Learners ◽  
Online Survey ◽  
Dynamic Assessment ◽  
Federal Legislation ◽  
Assessment Practices ◽  
Speech Language Pathologists ◽  
School Based

Purpose The purpose of this study was to ascertain the extent to which school-based speech-language pathologists' (SLPs) assessment practices with individual English learners (ELs) align with federal legislation and professional practice guidelines. Specifically, we were interested in examining SLPs' use of multiple tools during individual EL assessments, as well as relationships between practices and number of types of training experiences. Method School-based SLPs in a Midwestern state were recruited in person or via e-mail to complete an online survey pertaining to assessment. Of the 562 respondents who completed the survey, 222 (39.5%) indicated past or present experience with ELs, and thus, their data were included in the analyses. The questionnaire solicited information about respondent's demographics, caseload composition, perceived knowledge and skills and training experiences pertaining to working with ELs (e.g., graduate school, self-teaching, professional conferences), and assessment practices used in schools. Results The majority of respondents reported using multiple tools rather than a single tool with each EL they assess. Case history and observation were tools used often or always by the largest number of participants. SLPs who used multiple tools reported using both direct (e.g., standardized tests, dynamic assessment) and indirect tools (e.g., case history, interviews). Analyses revealed low to moderate positive associations between tools, as well as the use of speech-language samples and number of types of training experiences. Conclusions School-based SLPs in the current study reported using EL assessment practices that comply with federal legislation and professional practice guidelines for EL assessment. These results enhance our understanding of school-based SLPs' assessment practices with ELs and may be indicative of a positive shift toward evidence-based practice.

Holistic Communication Assessment for Young Children With Cleft Palate Using the International Classification of Functioning, Disability and Health:Children and Youth

2020 ◽  
Vol 51 (4) ◽  
pp. 914-938
Author(s):  
Anna Cronin ◽  
Sharynne McLeod ◽  
Sarah Verdon
Keyword(s):  
Young Children ◽  
Cleft Palate ◽  
Case History ◽  
Significant Others ◽  
International Classification ◽  
Assessment Tools ◽  
International Classification Of Functioning ◽  
Speech Language Pathologists ◽  
Holistic Assessment

Purpose Children with a cleft palate (± cleft lip; CP±L) can have difficulties communicating and participating in daily life, yet speech-language pathologists typically focus on speech production during routine assessments. The International Classification of Functioning, Disability and Health: Children and Youth Version (ICF-CY; World Health Organization, 2007 ) provides a framework for holistic assessment. This tutorial describes holistic assessment of children with CP±L illustrated by data collected from a nonclinical sample of seven 2- to 3-year-old children, 13 parents, and 12 significant others (e.g., educators and grandparents). Method Data were collected during visits to participants' homes and early childhood education and care centers. Assessment tools applicable to domains of the ICF-CY were used to collect and analyze data. Child participants' Body Functions including speech, language, and cognitive development were assessed using screening and standardized assessments. Participants' Body Structures were assessed via oral motor examination, case history questionnaires, and observation. Participants' Activities and Participation as well as Environmental and Personal Factors were examined through case history questionnaires, interviews with significant others, parent report measures, and observations. Results Valuable insights can be gained from undertaking holistic speech-language pathology assessments with children with CP±L. Using multiple tools allowed for triangulation of data and privileging different viewpoints, to better understand the children and their contexts. Several children demonstrated speech error patterns outside of what are considered cleft speech characteristics, which underscores the importance of a broader assessment. Conclusion Speech-language pathologists can consider incorporating evaluation of all components and contextual factors of the ICF-CY when assessing and working with young children with CP±L to inform intervention and management practices.

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