APPLIED PHYSICS VOLUME: 19 |NUMBER: 4 |2021 |DECEMBER
S udy o Scandium Based Ohmic Con ac s
o AlGaN/GaN He e os uc u es
G zego z ILGIEWICZ , Wojciech MACHERZYNSKI ,
Joanna PRAZMOWSKA-CZAJKA , And zej STAFINIAK , Regina PASZKIEWICZ
Depa men o Mic oelec onics and Nano echnology, Facul y o Mic osys em Elec onics and Pho onics,
W oclaw Uni e si y o Science and Technology, Janiszewskiego 11/17, 50-372 W oclaw, Poland
g zego z.ilgiewicz@pw .edu.pl, wojciech.mache zynski@pw .edu.pl, joanna.p azmowska@pw .edu.pl,
and zej.s a iniak@pw .edu.pl, egina.paszkiewicz@pw .edu.pl
DOI: 10.15598/aeee. 19i4.4134
A icle his o y: Recei ed Feb 28, 2021; Re ised May 27, 2021; Accep ed Aug 17, 2021; Published Dec 31, 2021.
This is an open access a icle unde he BY-CC license.
Abs ac . De elopmen o semiconduc o de ices
based on AlGaN/GaN he e os uc u e equi es s udy
and imp o emen o ohmic con ac s, whose necessa y
imp o emen lies in p ocess o checking new me allic
composi ions and he mal o ma ion p ocess pa ame-
e s. Usually, in me allic ohmic annealed con ac s
o AlGaN/GaN he e os uc u es, i anium is applied
as he i s laye , bu scandium may be an al e na-
i e. I was p o ed o be use ul o ob ain bo h ohmic
and Scho ky cha ac e is ics, depending on annealing
empe a u e o he con ac . In he p esen ed esea ch,
con ac s including scandium (Sc/Al/Mo/Au) we e ab-
ica ed, and, as e e ence sample, con ac s wi h i a-
nium including me allzia ion (Ti/Al/Mo/Au). Re e -
ence sample was annealed a 825 ◦C, and o ming em-
pe a u es o scandium con ac s we e 825 ◦C, 625 ◦C,
and 425 ◦C. All samples a e he mal o ma ion p o-
cess we e addi ionally hickened wi h Ru/Au bilaye .
To quickly compa e le el o me als in me alliza ion
mixing du ing o ma ion p ocess and o check applica-
bili y o EDS (Ene gy-Dispe si e X- ay Spec oscopy),
he simula ions o elec ons ajec o ies and EDS poin
scans we e pe o med.
Keywo ds
AlGaN/GaN, ohmic con ac , scandium.
1. In oduc ion
Fab ica ion o ohmic con ac s has ew pu poses. One
o hem is o ob ain as low con ac esis i i y as pos-
sible. The o he is o simpli y p epa a ion p ocess
keeping con ac ’s pa ame e s epea abili y. One solu-
ion is o look o con ac ’s mul ilaye me allic scheme
and i s p epa a ion condi ions esul ing in he bes
elec ical and physical pa ame e s. Usually, con ac ’s
composi ion consis s o ew me als chosen acco ding
o hei p ope ies. P obably annealed ohmic con-
ac s gain ohmic cha ac e is ics due o wo p ocesses.
One o hem is o ma ion o ni ogen acancies du ing
annealing p ocess. Ni ogen is abso bed by he i s
con ac ’s laye - i anium ha also abso bs oxygen
om he e os uc u e’s su ace and imp o es adhesion
o con ac s o semiconduc o . Ano he p ocess esul -
ing in ohmic cha ac e is ics is p obably di usion o alu-
minium h ough AlGaN/GaN he e os uc u e, which
allows o gene a e me allic connec ion be ween 2DEG
(Two Dimensional Elec on Gas) and con ac ’s me al-
liza ion [1]. The ole o o he laye s in con ac ’s com-
posi ion is o p o ec he men ioned Ti and Al laye s,
simul aneously allowing o ge low- esis ance elec i-
cal connec ion wi h de ices ou side con ac ’s s uc u e
(Au), and o p o ec he es o he con ac om gold
di usion du ing o ma ion p ocess (Mo). Al hough Ti
plays i s ole well, i s wo k unc ions sugges ob aining
sligh ly ec i ying con ac s wi h n-dopped AlGaN/GaN
he e os uc u e.
The e a e ew me als ha ha e lowe wo k unc-
ion and should also allow o ab ica e ohmic con-
ac s o used semiconduc o . One o hem is scan-
dium. Al hough i s pa ame e s sugges possibili y
o good e ec on ohmic con ac s pa ame e s, he e
a e no many s udies made on scandium applicabil-
i y o ohmic con ac s o AlGaN/GaN he e os uc u es
p oduc ion [2]. Mo e, bu s ill only ew wo ks, p esen
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esea ch on scandium usage in ohmic con ac s p o-
duc ion o n-GaN [2] and [3]. These sugges a i-
ous beha iou o scandium con ac s depending on o -
ma ion empe a u e. In he men ioned wo ks, scan-
dium in me alliza ions is used as monolaye ed con-
ac o co e ed only wi h gold. Only cha ac e is-
ics o con ac s a e checked. Elec ical pa ame e s
a e no p esen ed. To use his me al in ohmic con-
ac s, inding p ope me alliza ion scheme and o ma-
ion condi ions is necessa y. Acco ding o his e-
sea ch, me alliza ion scheme used in samples’ p epa-
a ion was he same as in he case o i anium-
including de ices: Sc/Al/Mo/Au. As e e ence sam-
ples, Ti/Al/Mo/Au me alliza ion scheme con ac s we e
p epa ed [4] and [5].
In p ocess o HEMT (High Elec on Mobili y T an-
sis o ) ab ica ion, o o he de ices based on Al-
GaN/GaN he e os uc u e including ohmic con ac s,
p ocess o deposi ion o addi ional gold laye is im-
po an . Role o addi ional laye is o educe shee
esis ance. Because o hea ing p ocess o me allic mul-
ilaye composed o hin laye s, he me alliza ion in-
g edien s mel pa ially, al hough hei mel ing em-
pe a u e is usually highe han RTP (Rapid The mal
P ocessing) empe a u e; excep aluminium wi h mel -
ing poin o 660 ◦C. Fo o he me als, mel ing poin s
a e: 1006 ◦C o gold, 1668 ◦C o i anium, 1541 ◦C
o scandium, 2623 ◦C o molybdenum. In di e en
RTP condi ions and using di e en hicknesses o lay-
e s, me alliza ion emel s di e en ly. Remel ing and
alloy o ma ion in me alliza ion ha e nega i e e ec
on shee esis ance, su ace condi ion and, in ex eme
cases, con ac may be damaged. Con ac des uc ion
occu s when gold a oms di use in o he e os uc u e.
To p o ec con ac om his nega i e e ec , s opping
laye is used. In his case, i is Mo laye . As i was
men ioned, Mo has mel ing poin equal o 2623 ◦C,
almos 1000 ◦C highe han he highes mel ing poin
o o he used me als. Bu in mel ing p ocess, alu-
minum dissol es o he me als - i anium o scandium
and molybdenum. Highly di usi e gold mixes pa ially
wi h Mo laye . In e ec , agglome a es o me als occu .
Gold laye mixed wi h molybdenum laye does no p o-
ec con ac as well as pu e gold. Elec ical pa ame-
e s o me alliza ion change. Usually, shee esis ance
inc eases. Reduc ion o shee esis ance may be ob-
ained by deposi ion o addi ional gold laye . How-
e e , adhesion o gold o con ac me alliza ion, de-
spi e he las gold laye , is weak. Adhesion imp o ing
he laye should be used. In his wo k, u henium was
used as adhesion laye .
2. Sample P epa a ion
All s eps in con ac s’ ab ica ion we e he same o all
samples, excep o ma ion empe a u es and i s me al
deposi ed in con ac s’ mul ilaye . S udied samples
we e AlGaN/GaN he e os uc u es g own by MOVPE
(Me alo ganic Vapo Phase Epi axy) p ocess. Mesa
s uc u es we e e ched by RIE (Reac i e Ion E ching)
p ocess using Cl2/BCl3/A plasma o he ab ica ed
TLM (T ans e Leng h Me hod) es s uc u es. Then,
in PVD (Physical Vapo Deposi ion) p ocess, he ol-
lowing me alliza ion mul ilaye s we e deposi ed:
•Ti (23 nm)/Al (100 nm)/Mo (45 nm)/Au
(190 nm),
•Sc (23 nm)/Al (100 nm)/Mo (45 nm)/Au
(190 nm).
Then, samples we e annealed in RTP p ocess.
Annealing ime o all samples was 60 s. Tempe a-
u es we e 825 ◦C o Ti/Al/Mo/Au me alliza ions and
825 ◦C, 625 ◦C and 425 ◦C o Sc/Al/Mo/Au me alliza-
ions. Then, a e o ma ion p ocess, a Ru (30 nm)/Au
(190 nm) bilaye was deposi ed.
(a) (b)
Au
Ru
AlGaN/GaN
Au
Mo
Al
Ti
(c)
Au
Ru
AlGaN/GaN
Au
Mo
Al
Sc
(d)
Fig. 1: Me alliza ion schemes be o e annealing (a, b) and a e
annealing and hickening p ocesses (c, d).
3. Measu emen s and Resul s
Fo pho oli hog aphy p ocess du ing samples’ p epa-
a ion, as la me alliza ion su ace as possible is im-
po an . Agglome a es and emel ing in con ac ’s
me alliza ion, a ec ing con ac ’s elec ic pa ame e s,
in luence also li -o p ocess used o p oduce hicken-
ing laye in he speci ic a eas. Insu icien ly la su -
ace p e en s p ope co e age sample wi h esis and
hus, p oblems wi h necessa y esis hickness, co e -
age and inally wi h shape o hickening laye may oc-
cu . To check samples’ su aces a e RTP p ocess,
samples we e examined by SEM (Scanning Elec on
Mic oscope) mic oscope (Fig. 2). Samples con ain-
ing i anium ha e he lowes shee esis ance (Tab. 1)
356 ©2021 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING
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Tab. 1: Elec ical pa ame e s o con ac s.
Me alliza ion
RTP emp. Deposi ed Annealed Thickened
(◦C) RsRsρcRsρc
(Ω·−1) (Ω·−1) (Ω·cm2) (Ω·−1) (Ω·cm2)
Ti/Al/Mo/Au 825 0.66 1.54 1.39 ·10−40.44 1.21 ·10−4
Sc/Al/Mo/Au 825 0.78 1.92 3.52 ·10−30.44 3.50 ·10−3
Sc/Al/Mo/Au 625 0.78 2.19 5.40 ·10−30.58 4.40 ·10−3
Sc/Al/Mo/Au 425 0.79 1.68 non ohmic 0.96 non ohmic
(a) (b) (c) (d)
Fig. 2: Samples a e RTP p ocess (uppe ) and a e hickening (bo om): a) Ti/Al/Mo/Au (RTP: T=825 ◦C), b) Sc/Al/Mo/Au
(RTP: T=825 ◦C), c) Sc/Al/Mo/Au (RTP: T=625 ◦C), and d) Sc/Al/Mo/Au (RTP: T=425 ◦C).
and hei su ace is cha ac e ized by speci ic emel ing
on me alliza ion’s edges (Fig. 2(a), uppe ). All sam-
ples including scandium look simila . All o hem show
me allic agglome a es. Di e ences a e in agglome a es’
size and amoun . Me alliza ion o sample annealed a
825 ◦C seems o be la e han o he s. On SEM im-
ages, i is isible ha dec ease in RTP empe a u e
inc eases he numbe o me allic agglome a es.
New me alliza ion adhesion o AlGaN/GaN he -
e os uc u e u ned ou o be good. Du ing con-
ac ’s p epa a ion p ocess, me alliza ion didn’ de-
ach om semiconduc o and edges a e no olded up.
To compa e scandium and i anium adhesion, addi-
ional esea ch should be conduc ed.
Shee esis ance o Sc including samples is he low-
es in he case o samples hea ed o 425 ◦C (Tab. 1).
Inc ease o 200 ◦C causes shee esis ance o inc ease.
Fu he inc ease o 200 ◦C allows o educe shee esis-
ance bu no so much as a 425 ◦C. The lowes shee
esis ance o all p epa ed samples occu ed in he case
o e e ence samples. In he case o con ac ’s esis i -
i y, he lowes one was ob ained o e e ence sample
(Ti/Al/Mo/Au, RTP: T=825 ◦C, see Tab. 1).
The samples wi h scandium including me alliza ion
o med a 425 ◦C u ned ou o ha e non-ohmic cha -
ac e is ics. Samples o med a 625 ◦C had esis i -
i y o con ac s equal o 5.40 ·10−3(Ω·cm2). Inc ease
in RTP empe a u e o nex 200 ◦C educed esis i -
i y 1.6 imes (3.52 ·10−3Ω·cm2) bu cha ac e is ics
o con ac s ob ained a lowe empe a u e had lowe
de ia ion om linea cha ac e is ics han in he case
o sample hea ed o highe empe a u e.
Despi e he di e en con ac ’s esis i i ies, he cha -
ac e is ics o scandium-including samples annealed a
825 ◦C and 625 ◦C we e simila . To check i he e we e
di e ences in cha ac e is ics no e iden on I-V plo ,
he di e en ial g aph o examined samples was d awn
(Fig. 3(c)). I was obse ed ha de ia ion om lin-
ea cha ac e is ics is highe in he case o scandium-
including sample o med a 825 ◦C han in he case
o he sample wi h he same ype o me alliza ion an-
nealed a 625 ◦C. The same measu emen s we e aken
o samples a e deposi ion o Ru/Au bilaye ( hick-
ened). In Tab. 1, shee esis ance esul s o samples
a e Ti/Al/Mo/Au and Sc/Al/Mo/Au deposi ion be-
o e RTP p ocess we e also included.
Nonohmic cha ac e is ics o deposi ed con ac s we e
no included o be p esen ed in Tab. 1 esul s. To check
me alliza ion su ace di e ence be ween annealed sam-
ples and hickened samples, SEM pho os o sam-
ples a e Ru/Au deposi ion we e included (Fig. 2).
Deposi ion o he Ru/Au hickening laye esul ed
in dec eased shee esis ance o all samples. Simila
shee esis ance was ob ained o bo h, Ti and Sc in-
©2021 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 357
APPLIED PHYSICS VOLUME: 19 |NUMBER: 4 |2021 |DECEMBER
(a) (b) (c)
Fig. 3: I-V cha ac e is ic o annealed samples (a), I-V cha ac e is ics o hickened me alliza ion samples (b) and di e en ials o
annealed samples (c).
Tab. 2: EDS measu emen s o composi ion o o med (F) and hickened (T) me alliza ions. Quan i ies in % o a oms.
Ti/Al/Mo/Au Sc/Al/Mo/Au
RTP T. 825 ◦C 825 ◦C 625 ◦C 425 ◦C
Elemen F T F T F T F T
O 14.5 2.5 24.6 3.7 15.3 4.2 11.6 4.4
N 9.4 9.6 11 15.5 13.5 17.8 10.6 13.7
Ga 5.1 1.4 6.5 1.7 1.3 1.2 2.5 1.3
Ti 8.3 0.2 – – – – – –
Sc – – 0.2 0.2 0.2 0.2 0 0
Al 18.8 2.2 14.4 1.5 21.6 2.2 21.7 3
Mo 13.2 3.9 9.3 3.1 12.6 3.4 12.2 3
Au 30.7 78.8 33 72.4 35.5 68.7 41.4 72.1
Ru – 1.4 – 1.9 – 2.3 – 2.5
(a) (b) (c) (d)
Fig. 4: Mon e Ca lo simula ions o elec on aces in me allic composi ions: a) Sc/Al/Mo/Au, b) Ti/Al/Mo/Au, c) hickened
Ti/Al/Mo/Au, and d) hickened Sc/Al/Mo/Au. Simula ions a e o no he mally o med composi ions.
cluding samples o med a 825 ◦C and i was equal
o 0.44 (Ω·−1).
Addi ionally, o es EDS poin scan applicabil-
i y o compa e he a oms’ di usion and me alliza-
ion emel ing le el in con ac s, he EDS scans we e
pe o med and compa ed o simula ions o elec ons
ajec o ies in me allic con ac mul ilaye composed
o pu e me als. The elemen s and hei con en s
in me alliza ions o examined con ac s a e p esen ed
in Tab. 2. I is di icul o de ine he dep h o EDS
scan, which is di e en o each me al and a ies
in me allic composi ion due o o ma ion p ocess. How-
e e , dep h o EDS scan o annealed me alliza ion
should be simila o pu e me al composi ion. To check
possible EDS scan dep h and possible ajec o ies
o elec ons in me allic con ac composed o pu e me -
als, he simula ions we e pe o med in CASINO so -
wa e [6]. An elec on beam wi h ene gy 15 keV was
simula ed, i.e., he same as in he case o EDS scan
o samples. Resul s o elec ons’ ajec o ies a e p e-
sen ed in Fig. 4. The sample o med in 425 ◦C is
he mos simila o no annealed sample, and o sim-
ula ed composi ions, because and du ing RTP p ocess
none o me alliza ion me als is a luid.
The lowes mel ing poin is o aluminium (660 ◦C).
As p esen ed in Fig. 4(a) and Fig. 4(b), elec on a-
jec o ies a e mainly in gold laye , pa ially in molybde-
num and aluminium laye s. Scandium laye is hin and
small numbe o elec ons eaches his laye . Con a y,
he e os uc u e laye is hick, so p obabili y o ob-
aining signals om he e os uc u e is high. Me al’s
a oms di usion inc eases wi h he inc easing empe -
a u e. Scandium, no de ec ed in sample o med a
425 ◦C, is de ec ed in he same le el in samples o med
a highe empe a u es and in samples a e hicken-
ing p ocess. This does no mean di usion o scan-
dium a oms du ing hickening p ocess. I is a e-
sul o di e en shape o elemen s’ signals ob aining
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olume. Gold quan i y di e ence be ween all o med
me alliza ions sugges s inc ease o gold di usion and
me als mixing wi h RTP empe a u e g ow h. Also,
du ing o ma ion p ocess, me als om he e os uc u e
di uses in o me alliza ion, which is eason o gallium
and ni ogen p esence in me alliza ion. High p esence
o i anium in Ti/Al/Mo/Au me alliza ion a e o ma-
ion, i s low p esence a e hickening, and low scan-
dium quan i y in all measu emen s sugges he highe
i anium han scandium di usion in he mal o ma ion
p ocess.
4. Conclusion
Resul s o esea ch on me alliza ion composi ion
o ohmic con ac s o AlGaN/GaN he e os uc u e
including scandium showed possibili y o ob ain-
ing good ohmic con ac s o med a lowe empe a-
u e, han in he case o Ti/Al/Mo/Au me alliza-
ion scheme. Howe e , nonohmic cha ac e is ics make
Sc/Al/Mo/Au me alliza ion annealed a 425 ◦C un-
usable o p oduce ohmic con ac s. I is possi-
ble ha modi ica ion o me allic laye s’ hickness
would allow using low empe a u e in ohmic con ac s
o AlGaN/GaN he e os uc u es’ ab ica ion p ocess.
Bo h esis i i y o con ac s and shee esis ances sug-
ges he bes pa ame e s o Sc including samples pos-
sible o be ob ained in con ac s o ma ion a empe a-
u es be ween 625 ◦C and 825 ◦C. In u u e esea ch,
hese samples should be ab ica ed and examined.
Su ace’s look sugges s ha o ob ain su ace o me -
alliza ion as la as possible, he empe a u es o an-
nealing should be close o 825 ◦C han 625 ◦C.
Wi h RTP p ocess empe a u e educ ion, he inal
shee esis ance aised a e addi ional laye deposi-
ion. I means ha addi ional bilaye does no change
shee esis ance o he speci ic alue bu in e ac s wi h
p e iously ab ica ed con ac and i s me alliza ion.
The same shee esis ances compa ed o shee esis-
ances o con ac ’s me alliza ions be o e he mal o -
ma ion p ocess show ha al hough e e y me allic com-
posi ion has speci ic shee esis ance (Ti/Al/Mo/Au
- 0.66 (Ω·−1), Sc/Al/Mo/Au - 0.78 (Ω·−1)),
he inal shee esis ance (a e hickening o con ac ’s
me alliza ion) is dependen on he p e ious he mal
o ma ion condi ions and i s dependence on me al-
lic scheme may be negligible. Con ac esis i i y e-
duc ion a e Ru/Au deposi ion seems o be in e es -
ing. Addi ional laye should no in luence he o med
con ac ’s esis i i y, because con ac ’s pa ame e s a e
se due o eac ions be ween me alliza ion and Al-
GaN/GaN he e os uc u e in o ma ion p ocess. Ad-
di ional laye s do no eac wi h p e iously p epa ed
con ac and i s me alliza ion. Howe e , measu es show
di e ences in esis i i y o con ac s in 19 % in he case
o Sc/Al/Mo/Au me alliza ion o med a 625 ◦C. Sam-
ples o med a 825 ◦C o bo h Ti and Sc me als ha e
small di e ence in con ac ’s esis i i y be o e and a e
hickening, which may be negligible. Howe e , because
no me alliza ion schemes, especially using scandium,
p oduce ohmic con ac s o AlGaN/GaN he e os uc-
u es, mo e esea ch should be made o ind he bes
me allic composi ion and o ma ion condi ions. Ex-
pe imen shows a possibili y o educ ion o o ma ion
empe a u e o 625 ◦C. Howe e , no only empe a-
u es be ween 625 ◦C and 825 ◦C a e p ope o p o-
duce ohmic con ac s using scandium as he i s me al-
lic laye . Di e en me alliza ion composi ion o med a
lowe empe a u e like 425 ◦C, o example wi h hin
scandium laye , may be use ul.
Di usion aises wi h empe a u e g ow h, so lowe
empe a u e allows o ob ain simila di usion le el be-
ween he e os uc u e, Sc and Al laye s. The e o e,
he hin scandium laye would allow a oms be ween
all h ee laye s o di use as e and allows o educe
empe a u e needed o ab ica e ohmic con ac s using
scandium. E ec s o empe a u e in luence on di usion
le el a e p esen ed in Tab. 2. Ti anium u ned ou
o be mo e di usi e han scandium, and i s amoun
in p ope me alliza ion is 8.3 % be o e hickening,
and 0.2 % a e hickening p ocess. I may sugges
using scandium, whose di usion a e and p esence
in o he laye s may be mo e p edic able han o i-
anium. Ru henium quan i y inc eases wi h dec ease
in empe a u e o RTP, bu hese laye pa ame e s
a e he same o all samples deposi ed in one p o-
cess. Di e ences include di e en shape o olume,
om which EDS scan ge s speci ic o a oms signals.
The EDS scan is good me hod o homogenous me al-
lic alloys. Con a y, when o ming he mul ilaye alloy
a high empe a u e, he esul may be use ul o as
compa ison o simila samples, bu no o check dep h
o p esence o elemen s’ a oms.
Acknowledgmen
This wo k was co- inanced by he Na ional Cen-
e o Resea ch and De elopmen g an s TECH-
MATSTRATEG No.1/346922/4/NCBR/2017, Pol-
ish Na ional Agency o Academic Exchange un-
de he con ac PPN/BIL/2018/1/00137 and W o-
claw Uni e si y o Technology K70W12D02 subsidy.
This wo k was accomplished hanks o he p od-
uc indica o s and esul indica o s achie ed wi hin
he p ojec s co- inanced by he Eu opean Union wi hin
he Eu opean Regional De elopmen Fund, h ough
a g an om he Inno a i e Economy (POIG.01.01.02-
00-008/08-05) and by he Na ional Cen e o
Resea ch and De elopmen h ough he Applied
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APPLIED PHYSICS VOLUME: 19 |NUMBER: 4 |2021 |DECEMBER
Resea ch P og am G an No. 178782 and G an
LIDER No. 027/533/L-5/13/NCBR/2014.
Au ho Con ibu ions
G.I. and W.M. ca ied ou he expe imen , G.I. w o e
he manusc ip wi h he assis ance o W.M. and R.P.
G.I., W.M., J.P.-C. and A.S. conduc ed de ice p o-
cesses o es s uc u es ab ica ion. G.I. and W.M.
o mula e he o iginal idea. R.P. supe ised he
p ojec .
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Abou Au ho s
G zego z ILGIEWICZ ecei ed his M.Sc.
om Chemical Engine ing om W oclaw Uni e -
si y o Technology in 2015. His esea ch in e es
include nonalloyed and low empe a u e ohmic con-
ac s o AlGaN/GaN he e os uc u es.
Wojciech MACHERZYNSKI ecei ed his
M.Sc. deg ee in Elec onic om W oclaw Uni-
e si y o Technology, Poland in 2005 and Ph.D.
deg ee om he W oclaw Uni e si y o Technology
in 2011. Now he is assis an p o esso a W oclaw
Uni e si y o Technology. His esea ch is ocused
on he echnology o semiconduc o s de ices in pa -
icula on de elopmen o he me al-semiconduc o
junc ion.
Joanna PRAZMOWSKA-CZAJKA ecei ed
M.Sc. deg ee (2005) and Ph.D. deg ee (2011)
om W oclaw Uni e si y o Technology. Since hen,
she has been assis an p o esso in Di ision o Mic o-
elec onics and Nano echnology, W oclaw Uni e si y
o Science and Technology. He cu en esea ch is
ocused on li hog aphy p ocess de elopmen o elec-
onic, op oelec onic de ices and gas senso s.
And zej STAFINIAK ecei ed M.Sc. deg ee (2008)
and Ph.D. deg ee (2015) in elec onics om W oclaw
Uni e si y o Technology. Since hen, he has been
assis an p o esso in Di ision o Mic oelec onics and
Nano echnology, W oclaw Uni e si y o Technology.
His cu en esea ch has ocused on de elopmen
o p ocess echnology and measu emen s o nanos uc-
u es based de ices.
Regina PASZKIEWICZ ecei ed he M.Sc.
deg ee (1982) in Elec ical Enginee ing om S .
Pe e sbu g Elec o echnical Uni e si y, Russia and
Ph.D. deg ee (1997) om he W oclaw Uni e si y
o Technology, Poland. Now she is ull p o esso a
W oclaw Uni e si y o Science and Technology. He
esea ch is ocused on he echnology o (Ga, Al, In)N
semiconduc o s and he de elopmen o echnological
p ocesses o mic owa e de ices and senso s.
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