Mark Somerville

Film thickness constraints for manufacturable strained silicon CMOS

This paper studies the effect of the strained silicon thickness on the characteristics of strained silicon MOSFETs on SiGe virtual substrates. NMOSFETs were fabricated on strained silicon substrates with various strained silicon thicknesses, both above and below the strained silicon critical thickness. The low field electron mobility and subthreshold characteristics of the devices were measured. Low field electron mobility is increased by about 1.8 times on all wafers and is not significantly degraded on any of the samples, even for a strained silicon thickness far greater than the critical thickness. From the subthreshold characteristics, however, it is shown that the off-state leakage current is greatly increased for the devices on the wafers with a strained silicon thickness that exceeds the critical thickness. The mechanism of the leakage was examined by using photon emission microscopy. Strong evidence is shown that the leakage mechanism is source/drain electrical shorting caused by enhanced dopant diffusion near misfit dislocations.

Fully depleted n-MOSFETs on supercritical thickness strained SOI

Strained silicon-on-insulator (SSOI) is a new material system that combines the carrier transport advantages of strained Si with the reduced parasitic capacitance and improved MOSFET scalability of thin-film SOI. We demonstrate fabrication of highly uniform SiGe-free SSOI wafers with 20% Ge equivalent strain and report fully depleted n-MOSFET results. We show that enhanced mobility is maintained in strained Si films transferred directly to SiO/sub 2/ from relaxed Si/sub 0.8/Ge/sub 0.2/ virtual substrates, even after a generous MOSFET fabrication thermal budget. Further, we find the usable strained-Si thickness of SSOI significantly exceeds the critical thickness of strained Si/SiGe without deleterious leakage current effects typically associated with exceeding this limit.

The Olin curriculum: thinking toward the future

In 1997, the F. W. Olin Foundation of New York established the Franklin W. Olin College of Engineering, Needham, MA, with the mission of creating an engineering school for the 21st century. Over the last five years, the college has transformed from an idea to a functioning entity that admitted its first freshman class in fall 2002. This paper describes the broad outlines of the Olin curriculum with some emphasis on the electrical and computer engineering degree. The curriculum incorporates the best practices from many other institutions as well as new ideas and approaches in an attempt to address the future of engineering education.

Determining dominant breakdown mechanisms in InP HEMTs

We present a new technique for determining the dominant breakdown mechanism in InAlAs-InGaAs high-electron mobility transistors. By exploiting both the temperature dependence and the bias dependence of different physical mechanisms, we are able to discriminate impact ionization gate current from tunneling and thermionic field emission gate current in these devices. Our results suggest that the doping level of the supply layers plays a key role in determining the relative importance of these two effects.

Breaking the ice with prospective students: a team-based design activity to introduce active learning

This paper discusses a short, team-based design activity that is simple to reproduce at any college. The activity involves designing and building structures from expanded polystyrene foam boards. Hot wire cutters allow students easily and safely to cut the foam into myriad shapes. After a one or two-hour period for design, manufacture, and test, there is a short period for construction. The activity has been used as part of recruitment and admissions process at Olin College. The activity is described in sufficient detail to allow others to reproduce it including an equipment and materials list and a suggested set of instructions. The results of the activity are discussed. The student teams generated a wide variety of structures and employed many different building strategies. The activity seems to promote a sense of comradry among the candidates as well as excitement about active learning methods.

Drowning in method, thirsty for values: A call for cultural inquiry

A decade or more has passed since publication of most calls for reform in engineering education. In the ensuing time, there has been significant work on the design, implementation, and transferability of appropriate methods and techniques - accompanied by, in most cases, little discussion of the values and beliefs of the people involved. But many theories of change rely on a fundamental shift in human beliefs and values, and purport that institutionalization of methods is impossible without this shift. Given this, now may be a reasonable time to re-visit the questions: What are the values of people involved in engineering education, and are our educational reform efforts considering these values throughout the curriculum design process? In this paper, we examine several models for engineering educational reform, with a particular focus on the role of individual values in determining responses to change. We highlight the importance of developing understandings of individual perspectives and social context. We contrast a user-oriented approach to curriculum design with common scenarios of curriculum design practice, and we argue that, in many cases, successes in curricular change can be traced to employment of user-centered approaches.

Work in Progress: Understanding Discomfort: Student Responses to Self-Direction

The literature consistently reports that students express some degree of discomfort when they are thrown into self-directed learning environments. In this paper, we present the preliminary results of an investigation of the causes of student discomfort in several different self-directed project-based courses. Our results suggest that student motivation and opportunities for the development of deep understanding and transferable skills are important in creating a positive self-directed learning experience. Negative experiences and student discomfort in self-directed environments may stem from problems with self-regulation, low self-perceptions of content learning, lack of personal engagement with the topic, and difficulties related to the social learning environment

Model collaboration for advancing student-centered engineering education

The University of Texas at El Paso (UTEP) and the Franklin W. Olin College of Engineering (Olin) are establishing a student-centered hands-on interactive approach to engineering education (similar to Olins) at UTEP, where it will reside in UTEPs innovative B.S. in Leadership Engineering (LE) program. The goal of the proposed collaboration is to catalyze UTEPs educational innovation through a cross-campus collaboration between the two institutions by incorporating the Olin educational process, both design and features, into the first offerings of the Bachelor of Science in Leadership Engineering (BSLE) program. Specifically, the collaboration includes faculty exchanges between the two institutions; a series of retreats for planning and assessment; curriculum development; and student recruitment practices. The 21st century workplace demands a new engineer - one who effectively contributes to solving problems using innovation, creativity, and strategic foresight. Graduates of the Olin-UTEP developed Bachelor of Science in Leadership Engineering (LE) program will possess these attributes through the programs rigorous yet flexible major in engineering, and in-depth study of leadership and its effect upon technology and society. In this panel we will share the context for our innovative approach, key features of the partnership to date, and acclaim the value of inter-institutional sharing.

Work in progress - a provisional competency assessment system

Over the last two years Olin College has been defining and implementing a provisional system to develop and assess student competency levels. The system particularly emphasizes the importance of creating a community of practice that includes not only faculty but also staff and students. In this paper we provide an overview of the design process, and comment on the results of our first year of implementing the system

Non-Traditional Assessments for New Learning Approaches: Competency Evaluation in Project-Based Introductory Materials Science

Over the last twenty years, NSF and the engineering community have called for systemic changes in engineering education, including an emphasis on contextual understanding; increased teaming skills, including collaborative, active learning; and an improved capacity for life-long, self-directed learning. In addition, ABET has called for engineering graduates that demonstrate an ability to apply science and engineering, and ABET requires assessment processes designed to measure student achievement of learning outcomes. Olin College has responded to these calls for change by embracing new learning approaches and assessment techniques, and by developing project-based courses that encourage experiential understanding of content and aid the development of life-long learning skills. To address the assessment needs of new pedagogical approaches, Olin recently instituted a competency based assessment system to accompany the traditional course grading system already in place. The thread of competency assessments provides grading coherency for both faculty and students, and it provides students with valuable information concerning their development of nontraditional skills that they could use to identify shortcomings and further their learning. In this paper, we describe the new pedagogical approaches in Olins introductory materials science course, and we explain our implementation of the competency assessment system to measure student attainment of both materials science knowledge and broader skills such as teaming, communication, and experimental inquiry.