Physics of InAIAs/InGaAs Heterostructure Field-Effect Transistors

Contains an introduction, reports on three research projects, research conclusions and a list of publications.Joint Services Electronics Program Contract DAAHO4-95-1-003

Multiscale Metrology and Optimization of Ultra-Scaled InAs Quantum Well FETs

A simulation methodology for ultra-scaled InAs quantum well field effect transistors (QWFETs) is presented and used to provide design guidelines and a path to improve device performance. A multiscale modeling approach is adopted, where strain is computed in an atomistic valence-force-field method, an atomistic sp3d5s* tight-binding model is used to compute channel effective masses, and a 2-D real-space effective mass based ballistic quantum transport model is employed to simulate three terminal current-voltage characteristics including gate leakage. The simulation methodology is first benchmarked against experimental I-V data obtained from devices with gate lengths ranging from 30 to 50 nm. A good quantitative match is obtained. The calibrated simulation methodology is subsequently applied to optimize the design of a 20 nm gate length device. Two critical parameters have been identified to control the gate leakage magnitude of the QWFETs, (i) the geometry of the gate contact (curved or square) and (ii) the gate metal work function. In addition to pushing the threshold voltage towards an enhancement mode operation, a higher gate metal work function can help suppress the gate leakage and allow for much aggressive insulator scaling

Multiscale Metrology and Optimization of Ultra-Scaled InAs Quantum Well FETs

A simulation methodology for ultra-scaled InAs quantum well field effect transistors (QWFETs) is presented and used to provide design guidelines and a path to improve device performance. A multiscale modeling approach is adopted, where strain is computed in an atomistic valence-force-field method, an atomistic sp3d5s* tight-binding model is used to compute channel effective masses, and a 2-D real-space effective mass based ballistic quantum transport model is employed to simulate three terminal current-voltage characteristics including gate leakage. The simulation methodology is first benchmarked against experimental I-V data obtained from devices with gate lengths ranging from 30 to 50 nm. A good quantitative match is obtained. The calibrated simulation methodology is subsequently applied to optimize the design of a 20 nm gate length device. Two critical parameters have been identified to control the gate leakage magnitude of the QWFETs, (i) the geometry of the gate contact (curved or square) and (ii) the gate metal work function. In addition to pushing the threshold voltage towards an enhancement mode operation, a higher gate metal work function can help suppress the gate leakage and allow for much aggressive insulator scaling

Physics of InAIAs/InGaAs Heterostructure Field-Effect Transistors

Contains an introduction, a report on one research project and a list of publications and conference papers.Joint Services Electronics Program Contract DAAH04-95-1-0038Texas Instrument

Physics of Hemterostructure Field-Effect Transistors

Contains an introduction, report on one research project and a list of publications.Joint Services Electronics Program Contract DAAH04-95-1-0038Texas Instruments Agreement dated 11/23/9

Physics of InAIAs/InGaAs Heterostructure Field-Effect Transistors

Contains an introduction, reports on two research projects and a list of publications and conference papers.Charles S. Draper Laboratories Contract DL-H-441694Joint Services Electronics Program Contract DAAL03-92-C-0001Texas Instruments Agreement dated 08/14/9

III-V compound semiconductor transistors—from planar to nanowire structures

Conventional silicon transistor scaling is fast approaching its limits. An extension of the logic device roadmap to further improve future performance increases of integrated circuits is required to propel the electronics industry. Attention is turning to III-V compound semiconductors that are well positioned to replace silicon as the base material in logic switching devices. Their outstanding electron transport properties and the possibility to tune heterostructures provide tremendous opportunities to engineer novel nanometer-scale logic transistors. The scaling constraints require an evolution from planar III-V metal oxide semiconductor field-effect transistors (MOSFETs) toward transistor channels with a three-dimensional structure, such as nanowire FETs, to achieve future performance needs for complementary metal oxide semiconductor (CMOS) nodes beyond 10 nm. Further device innovations are required to increase energy efficiency. This could be addressed by tunnel FETs (TFETs), which rely on interband tunneling and thus require advanced III-V heterostructures for optimized performance. This article describes the challenges and recent progress toward the development of III-V MOSFETs and heterostructure TFETs—from planar to nanowire devices—integrated on a silicon platform to make these technologies suitable for future CMOS application

Physics of InAIAs/InGaAs Heterostructure Field-Effect Transistors

Contains an introduction, reports on two research projects and a list of publications.Joint Services Electronics Program Contract DAAL03-92-C-0001Joint Services Electronics Program Grant DAAH04-95-1-0038Raytheon Corporation Contract 90-58203Texas Instruments Agreement dated 08/14/9

Relación óptima de metionina+cistina/lisina digestibles en gallinas isa Brown de 34 a 42 semanas de edad.

Los trabajos previos en los que se han estudiado las recomendaciones de metionina+cistina para gallinas ponedoras son muy numerosos, pero los resultados obtenidos presentan una gran variabilidad y, en algunos casos, son contradictorios. Esta variabilidad se explica por las condiciones en las que se ha realizado el estudio, la edad de las gallinas, la genética y el parámetro a optimizar. En este sentido, Novak et al. (2004) observaron que las necesidades totales de metionina+cistina eran mayores para maximizar el peso del huevo que para optimizar la producción de huevos o la eficacia alimenticia. Estas diferencias fueron menos importantes entre las 20 y 43 semanas (8%), que de las 44 a las 63 semanas de edad (16%). Además, las recomendaciones para optimizar la producción y el peso del huevo fueron un 17% y 11% mayores, respectivamente, en el primer periodo con respecto al segundo. Por el contrario, Waldroup y Hellwig (1995) encontraron que las necesidades totales de metionina+cistina para optimizar la producción y masa de huevo fueron más elevadas (12 y 10%, respectivamente) de 51 a 71 semanas de edad que de 25 a 45. Cuando las recomendaciones se expresan en unidades digestibles, el rango de necesidades de metionina+cistina digestibles con respecto a lisina digestible varía desde un 81 a un 107% (81%: Coon and Zhang, 1999; 90%: FEDNA, 2008; 91%: Rostagno et al., 2005; 93%: CVB, 1996; 94%: Bregendahl et al., 2008; 99%: Brumano et al., 2010a; 100%: Cupertino et al., 2009; Brumano et al., 2010a; 101%: Brumano et al., 2010b; 107%: Schmidt et al., 2009). Como consecuencia de esta alta variabilidad, es necesario seguir investigando sobre cuál sería el ratio óptimo metionina+cistina/lisina digestible para optimizar los rendimientos de gallinas ponedoras. Por tanto, el objetivo de este trabajo es determinar las necesidades óptimas de metionina+cistina digestibles con respecto a lisina digestible de gallinas Isa Brown desde las 34 a las 42 semanas de eda

Los aminoácidos azufrados mejoran la eficacia de utilización del pienso.

Las recomendaciones de metronina+ostina obtenidas a partir de diferentes estudios presentan una gran variabilidad, por lo que es necesario investigar cuál es la relación óptima metronina+ostina /lisina digestible para optimizar los rendimientos de gallinas ponedoras