Tehnici nanolitografice pentru fabricarea dispozitivelor ... - ICPE-CA

12 October 2012
Tehnici nanolitografice pentru fabricarea
dispozitivelor nanoelectronice
Adrian Dinescu, IMT Bucuresti
Workshop “Parteneriat pentru inovare: cercetare – industria electronica”

18 October 2012
Nanoscale Structuring and Characterization Laboratory
Raith e_Line - dedicated EBL equipment NanoInk Nscriptor – dip pen nanolithography
Tescan Vega LMU II
Thermionic (tungsten) SEM
FEI Nova NanoSEM630
FEG-SEM
NT-MDT Ntegra Aura AFM & STM
Agilent G200 - Nanoindenter

First EBL equipment in IMT - Tescan Vega LMU II
and Raith Elphy Plus – installation 2006 Raith e-Line – installation 2008
18 October 2012
Smallest beam diameter : 5nm @ 3pA
beam current and 30kV
100nm
Electron Beam Lithography equipment in IMT Bucharest
30nm diameter holes in PMMA 950k
Smallest beam diameter: 1.5nm @ 200pA
150nm
̴ 10nm diameter holes in PMMA 950k

600µm
18 October 2012
Mix and match lithography: photolitography & EBL
200µm

18 October 2012
Acoustic devices for GHz applications
Acoustic resonators
A.Muller, D. Neculoiu, G. Constantinidis, G. Deligeorgis, A. Dinescu, A. Stavrinidis, A. Cismaru, M. Dragoman and A. Stefanescu,
„ SAW Devices manufactured on GaN/Si for frequencies beyond 5GHz”, IEEE Electron Device Letters, Vol. 31, No. 12, Dec. 2010
D. Neculoiu, A. Müller, G. Deligeorgis, A. Dinescu, A. Stavrinidis, D. Vasilache, A. Cismaru, G. E. Stan and G. Konstantinidis,
“AlN on silicon based surface acoustic wave resonators operating at 5 GHz”, Electronics Letters, vol 45, No 23, 2009

18 October 2012
AlN/Si
•Deposition by magnetron sputtering
•Sound velocity 6000 m/s
•Coupling coefficient ̴ 6%
GaN/Si
•Deposition by MBE and MOCVD
•Sound velocity 5000 m/s
•Coupling coefficient ̴ 2%
•Monolithic integration with HEMT
transistors is possible
SAW devices for microwave applications (1)
HEMTs
SAWs
Collaboration IMT Bucharest – FORTH IESL Heraklion, Grece

GDSII layout for contact
pads and alignment marks
18 October 2012
Detail of Ti/Au
nanoelectrodes
SAW devices for microwave applications (2)
Photolithography
Metallization
(Cr/Au)
Lift off
Wafer patterned with Cr/Au
contact pads
SAW resonator after
metallization and lift off
+
E-beam evaporation
(Ti/Au)
Lift off
GDSII layout of the IDTs
EBL
IDTs patterned in PMMA 950k

SAW devices for microwave applications (5)
Results 2009
Resonance > 5GHz on AlN
D. Neculoiu, A. Müller, G. Deligeorgis, A. Dinescu, A.
Stavrinidis, D. Vasilache, A. Cismaru, G. E. Stan and G.
Konstantinidis, “AlN on silicon based Surface Acoustic
Wave resonators operating at 5 GHz”
-70
4.6 4.8 5
frequency, GHz
5.2 5.4
Electron. Lett. 45, 1196 (2009) Best previous result obtained before was a SAW on
AlN (but on diamond not on silicon) operating at 4.5
GHz [P. Kirsch et al. Appl Phys. Lett.88, 223504,
2006]
18 October 2012
S21, dB
-40
-45
-50
-55
-60
-65

18 October 2012
SAW devices for microwave applications (6)
SEM micrograph of the test structure. The distance between the IDTs was d = 20 µm;
for the other test structures, it was d = 100, 200, and 600 µm.
Detail of the nanolithographic process with fingers and interdigits which are
nominally 200-nm wide, developed on the GaN surface.
(a) SEM photograph. (b) AFM image.
A.Muller; D.Neculoiu; G.Konstantinidis; G. Deligeorgis; A. Dinescu; A.
Stavrinidis; A. Cismaru; M.Dragoman; A.Stefanescu; “SAW Devices
Manufactured on GaN/Si for Frequencies Beyond 5 GHz “
IEEE ELECTRON DEVICE LETTERS Volume: 31 Issue: 12 Pages:
1398-1400 1398 1400 (2010)
Results 2010
Resonance > 5GHz on GaN
Measured reflection losses (S11) versus the frequency for three
structures with different distances between the IDTs compared
with the electromagnetic simulated results (without the
inclusion of the piezoelectric effect).
The highest resonance frequency reported for a SAW structure on GaN (on sapphire) is
2.225 GHz, with the interdigitated transducer (IDT) having 600-nm-wide fingers and
spacings: T. Palacios, F. Calle, E. Monroy, and F. Munoz, “Submicron technologyfor IIInitride
semiconductors,” J. Vac. Sci. Technol. B, Microelectron. Process. Phenom., vol.
20, no. 5, pp. 2071–2074, Sep. 2002.

SAW, single resonator; length 100 µm
IDTs, digit/interdigit spacing 0.2 µm;
Distance between reflectors and IDTs:
d= 0.95 µm;
IDT: 100 fingers/interdigits ; reflectors
60 digits /interdigits
GaN/Si; GaN layer 1 µm thin
IDT and reflectors 0.1 µm thin Au
18 October 2012
SAW devices for microwave applications (7)
SmartPower - Smart integration of GaN & SiC high power electronics for industrial
and RF applications. (www.smart-power.com)
Experiments to prove the concept of monolithic integration of MMIC and GaN T sensor.
Q = 400
Sensitivity ~ 356.9 kHz/°C
= 65 ppm/°C

18 October 2012
MSM photodetectors on silicon supported GaN membranes
Schematic cross-section of the membrane
MSM UV detector structure.
Top view of the detector Detail of the interdigitated contacts
a) Responsivity vs wavelength for the 0.5µm finger/interdigit UV GaN detector before the silicon substrate removal.
b) Responsivity vs wavelengthfor the 0.5 µm finger/interdigit UV detectorst manufactured on thin GaN membrane.
1. A.Muller, G. Konstantinidis, M. Dragoman, D. Neculoiu, A. Dinescu, M. Androulidaki, M. Kayambaki, A. Stavrinidis, D. Vasilache, C. Buiculescu, I. Petrini, A. Kostopoulos and
D. Dascalu, “GaN Membrane-supported UV Photodetector manufactured using nanolithographic process” , Microelectronics Journal; ,40,2009, p 319-321.
2. A. Müller, G. Konstantinidis, M. Androulidaki, A. Dinescu, A. Stefanescu , A. Cismaru , D. Neculoiu , E. Pavelescu, A. Stavrinidis, “Front and backside-illuminated GaN/Si
based metal–semiconductor–metal ultraviolet photodetectors manufactured using micromachining and nano-lithographic technologies”, Thin Solid Films, 520 (2012)
2158–2161

Schematic cross-section of the membrane
MSM UV detector structure.
18 October 2012
MSM photodetectors on silicon
E. Budianu, M. Purica, A. Dinescu, E. Manea “Metal-Semiconductor-Metal photodetector on silicon insulating wafers
based on nanoscale interdigitated electrodes”, EMRS Fall meeting 2009, September 14-18, Warsaw, Poland

18 October 2012
AFM image of the SLG
Equipment: NT-MDT N-Tegra Aura
Intensity (a. u.)
1581.0
EBL for graphene based devices
2656.7
1 500 2 000 2 500 3 000 3 500 4 000
Raman shift (cm -1 )
Intensity (a. u.)
1583.2
A.C. Ferrari et. al., Pyhs. Rev. Lett. 97 , 187401 (2006)
MLG BLG SLG
2657.6
1 500 2 000 2 500 3 000 3 500 4 000
Raman shift (cm -1 )
Intensity (a. u.)
1586.1
2640.7
1 500 2 000 2 500 3 000 3 500 4 000
Raman shift (cm -1 )
Raman spectra of a few selected points of graphene flake used for FET fabrication
Substrate: p ++ silicon, boron doped, resistivity 0.005 Ωcm, covered with 300nm dry thermal oxide

18 October 2012
SLG areas surrounded by alignment marks

18 October 2012
Patterned electrical contacts on graphene flakes

18 October 2012
CPW structures on SLG

18 October 2012
Cutting process for
SLG
- Electronresist
-SLG
-Silicon dioxide
-Silicon
Electron resist deposition
EBL exposure
RIE (oxygen plasma)
Electron resist removal
E-beam lithography patterning of graphene flake
RIE etching (oxygen plasma) of graphene flake

18 October 2012
Intensity (a. u.)
1588.1
2642.8
1 500 2 000 2 500 3 000 3 500 4 000
Raman shift (cm -1 )
Electrical contacts for source and drain fabricated by e-beam lithography, metal
evaporation (Ti/Au- 5-30nm), and lift-off

18 October 2012
Pristine SLG
Graphene patterned for RIE
Patterning in the PMMA before metal coating The structre with 20 transistors after lift-off
Array of 17 back gated FETs on graphene ribbons
Graphene ribbons
A back gated FET on
graphene ribbon

Rds (kΩ)
Semiconductor Characterization System - 4200-SCS/C/Keithley
with Wafer Probing Station –Easyprobe EP6/ Suss MicroTec
18 October 2012
14
12
10
8
6
4
2
0
-40 -30 -20 -10 0 10 20 30 40
Back gate voltage (V)
R d s i n th e C N P (k Ω )
80
70
60
50
40
30
20
10
The device under test, on the probing station
0
0 200 400 600 800 1000 1200
Dose (µC/cm2)
Rds in the CNP vs irradiation dose (HV = 200V)
Similar behavior at 500V and 1kV

18 October 2012
EBID module
SEM micrographs showing platinum lines connecting a polymer nanowire to the electrical pads
L. Gence, V. Callegari, A Dinescu, S. Melinte and S. Demoustier-Champagne, “Hybrid Polymer nanowire based electronic devices correlated characterization”
14-th International Conference of Modulated Semiconductor Structures (MSS 14), 19-24 July 2009, Kobe, Japan

• Project: Carbon nAnotube Technology for High-speed nExt-geneRation nano-
InterconNEcts – CATHERINE (FP7/STREP, 2008-2010)
Structure used for electrical characterization of CNTs
at high frequencies. EBL was used for patterning the
small calibration line and EBID technique for fixing
the CNTs
18 October 2012
Platinum deposition was used for fixing the CNTs
across V-shaped trenches in order to measure their
mechanical properties