electronics, microelectronics, nanoelectronics, … part ii

Budapest University of Technology and Economics

Department of Electron Devices

eet.bme.hu

Electronics, microelectronics, nanoelectronics, …

Part II

Mizsei, János www.eet.bme.hu

© BME Department of Electron Devices, 2012.eet.bme.hu February 6, 2013

Outlinenanoscale effects•3-2-1-0 dimensions•atomic scales: different transport mechanisms (thermal, electrical, mechanical)

technology at nanoscale•lithography by nanoballs•nanoimprint•Langmuir-Blodgett technology•MBE – molecular beam epitaxy•FIB – focused ion beam •AFM, STM processes

nanoscale devices•QWFET•single electron devices•nanotubes •nanorelays •organic molecular integrated circuits •vacuum-electronics•spintronics •kvantum-computing•oxide electronics •thermal computing

© BME Department of Electron Devices, 2012.eet.bme.hu

Nanoscale effects

February 6, 2013

• density of states for 3

2 1 0 dimension objects

• tunnelling

• surface/interface scattering

• ballistic transport


Technologies at nanoscale

February 6, 2013

•lithography by nanoballs•nanoimprint•Langmuir-Blodgett technology•MBE – molecular beam epitaxy•FIB – focused ion beam •AFM, STM processes


Lithography by nanoballs


Nanoimprint

February 6, 2013


Nanoimprint


Langmuir-Blodgett technology

February 6, 2013

for molecular monolayer


MBE – molecular beam epitaxy

February 6, 2013

Computer controlled evaporation (PVD)


MBE – molecular beam epitaxy


FIB – focused ion beam


FIB – focused ion beamApplications of FIB:

•cross-sectional imaging through semiconductor devices (or any layered structure)•modification of the electrical routing on semiconductor devices•failure analysis•preparation for physico-chemical analysis•preparation of specimens for transmission electron microscopy (TEM) or other analysis•micro-machining•mask repair


FIB – focused ion beam

FIB drilled nanohole for thermal nanoswitch with Pt overlayer


AFM processes

February 6, 2013

Hotplate for AFM excited agglomeration and peel off

Nanostructures by AFM tip excitation of hot (120 oC) silver nanolayers


AFM processes

February 6, 2013

Quantum corall by AFM tip (Fe on Cu surface)


AFM processes: anodic oxidation by AFM tip

February 6, 2013


Microscopic charges on SiO2

surfaces

100 nm native oxideoxide

Si: P type, <100>, 10 ohmcm


Charging process:(AFM, “conducting wire”)

Measuring process:Measuring process:(Kelvin electric force microscopy)(Kelvin electric force microscopy)

Low resolution, compared to the charging process !


11:30:29 AM Fri Aug 19 2005

04:11:07 PM Thu Aug 18 2005 04:11:07 PM Thu Aug 18 2005 3 V

2

1

-1

-2

-3

3 V

2

1

-1

-2

-3


04:11:07 PM Thu Aug 18 2005 04:11:07 PM Thu Aug 18 2005

11:30:29 AM Fri Aug 19 2005

3 V

2

1

-1

-2

-3

3 V

2

1

-1

-2

-3

Only after 300 C heat treatment !


Microscopic charge on the SiO2

surface

Extremely high and inhomogeneous electric field:

700000V/m


Nanoscale devices

February 6, 2013

• QWFET• single electron devices• nanotubes • nanorelays • organic molecular

integrated circuits • vacuum-electronics• spintronics • oxide electronics • thermal computing


QWFET – quantum well fet• low bandgap enables

lower supply voltage• higher bangap substrate

helps to keep electrons in the channel

• higher mobility results in higher current

Schottky-barrier type (depletion) device


QWFET

Problematic point: compound semiconductor in Si based technology


Advantages of QWFET

higher speed at lower power dissipation


Single electron transistor - SET


Fabrication of SET by STM tip anodisation


Single electron devices: charge-memorySET read-out

February 6, 2013

•50 nm head-surface distance

•~10 nm grain size

•~10 Terabit/inch2


Carbon

diamond

graphite

February 6, 2013


Graphene, carbon nanotubes


Carbon nanotubes as quantum wires

density of states depending of chirality


Carbon nanotube devices: CNT


Micro-, and nanorelays

Nanorelaysnanorelays: instable mechanical movement, stick down


Atom relay transistor (ART)

Molecular single electron switching transistor (MOSES)


Organic molecular integrated circuits



~100 nm2



Problems with the organic molecular ICs: • technology (it has not been realised until now) • metal contacts and wires (atomic contact)• chemical instability• slow operation depending on number of

electrons/bit ratio


Vacuum-electronics: nanosised „Vacuum tube”

Vertical field emission: Lateral field emission:

MOSFET- likegated devices


Field emissionby gate control


Technology

resist plasma treatment and reflow


Characteristics of the nanosised „Vacuum tube”


Spintronics, Stern-Gerlach experiment

February 6, 2013


Spin: Einstein–de Haas effect

Switch on and off with the resonance frequency of the suspended mass


GMR - giant magnetoresistance

February 6, 2013

Low resistance high resistance


Spin- valve MRAM


Spin- transistor on

February 6, 2013


Spin- transistor off

February 6, 2013


Quantum dot (QD) logika

Inverter


Oxide electronics

February 6, 2013


(A) In high resistance state, there is a lack ofoxygen vacancies at the interface. Carriers must overcome Schottky barrierto contribute to current. (B) In low resistance state, oxygen vacancies accumulateat the interface, reducing depletion width such that tunneling is possible

Oxygen vacancy drift bipolar switching mechanismfor representative n-type oxide


Switchable Pt/TiOx/Pt rectifier

February 6, 2013

Opposite polarityvoltage pulses control location of oxygen vacancies, which determineswhich contact is rectifying and which is Ohmic


Experimental demonstration of spike-timing dependentplasticity (STDP) in Pt/Cu2O/W device

Appl. Phys. A, S.-J. Choi, G.-B. Kim, K. Lee, K.-H. Kim, W.-Y.Yang, S. Cho, H.-J. Bae, D.-S. Seo, S.-I. Kim, and K.-J. Lee, Synapticbehaviors of a single metal–oxide–metal resistive device, 102, 1019, 2011

(A) I-V curves of MIM deviceshowing bipolar resistive switching.

(B) For t>0 (pre-synaptic pulsefires before post-synaptic pulse), the synaptic weight increases, while for t<0, the synaptic weight decreases, in accordance with STDP.


„Nothing beats scaled silicon but nanotechnology can complement”


Ethical issues concerning the nanotechnology

- „nano” is a good idea and a good word to get money from the government or from the EU

- many nanoobject have not fully been tested, some of them could be dangerous for health (?)

- self replicating nanomachines may live their own life -> catastrophe ?

- …


Problems with CMOS

device limits (6 or even more interfaces)

scale down: depletion layers, gate-tunnel current -> direct tunnel distance: 2 nm)


Problems with the nano self-replicated machines

Budapest University of Technology and Economics

Department of Electron Devices

eet.bme.hu

End of part II

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electronics, microelectronics, nanoelectronics, … part ii

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