ElectronicsMacro, Micro and Nano

1
Electronics-Macro, Micro and Nano
2
Vacuum tubes
Developed in the early 1900s. Used until the
1970s
Triode (three terminal device)
Filament (cathode) biased with a negative
voltage, emits electrons Plate (anode) biased
with a positive voltage, attracts electrons Grid
biased negative with respect to cathode
3
Vacuum tubes
Triode (three terminal device)
Small voltage on the grid controls the current
between cathode and anode. Three terminal
device with gain!
But. Electrons boiled off filament, requires
a lot of power (heat) High voltages required on
the anode
Also pentodes, hexodes, heptodes, octodes,
nonodes.
4
Transistors
npn transistor
Small voltage on the base controls current
between emitter and collector
Made from a single piece of silicon n-type
regions are doped to make them
electron-rich p-type regions are doped to make
them hole-rich
5
Transistors
6
Discrete Circuits
With transistors and other discrete components,
one could make sophisticated discrete circuits
7
Integrated circuits
Integration of all components (transistors,
resistors capacitors), etc on a single chip
8
Integrated circuits
Integration of all components (transistors,
resistors capacitors), etc on a single chip
First Intel microprocessor, the 4004, containing
2250 transistors (1971)
9
Integrated circuits
300 mm wafer containing Pentium 4 devices Each
device contains 125-180 million transistors
10
Fabrication techniques
Photolithography
Substrate is typically oxidized Si, but can be
anything
11
Fabrication techniques
Photolithography
Deposit photoresist--typically by spin-coating
12
Fabrication techniques
Photolithography
Expose pattern on photomask using light Typically
Deep Ultraviolet (DUV) 250 nm wavelength Contact
or projection lithography
13
Fabrication techniques
Photolithography
Develop photoresist, left with pattern on surface
14
Fabrication techniques
Photolithography
Transfer pattern to substrate First
technique--etching
silicon
Remove residual photoresist
Etch silicon oxide
15
Fabrication techniques
Photolithography
Transfer pattern to surface Second
technique--deposit material
metal
Deposit metal
Remove photoresist
16
High resolution techniques
High resolution electron beam lithography
17
Gallery of electron-beam fabricated samples
GaAs 2DEG double-quantum dot
F-SQUID Ferromagnetic/superconductor structure
Ferromagnet/superconductor/normal metal device
DNA/Au nanoparticle device
18
Gallery of electron-beam fabricated samples
Graphene sheet
Multiwall carbon nanotube
19
Other fabrication techniques
Photolithography allows one to expose large
areas but its resolution is limited E-beam
lithography has higher resolution, but it is a
serial process, takes a long
time Other techniques X-ray lithography
parallel like optical lithography
but x-rays expensive and
difficult to control focused ion beam
micro and nano-etching
serial process --takes long residue
(debri) left from etching
20
More recent fabrication techniques
Microcontact printing
From IBM Research, Zurich
21
More recent fabrication techniques
Dip Pen Nanolithography (S. Hong, R. Piner,
Mirkins group, Northwestern)
MSU group