© 2025 IEEE. This is he au ho ’s e sion o he wo k accep ed o publica ion in 2025 37 h In e na ional Symposium on Powe
Semiconduc o De ices and ICs (ISPSD).
The inal e sion o eco d is published in IEEE Xplo e a : h ps://doi.o g/10.23919/ISPSD62843.2025.11117512
Plasma Beha io o SiC MOSFETs wi h
Enginee ed Subs a es du ing Re e se Reco e y
Mohamed Alaluss
Chai o Powe Elec onics
Chemni z Uni e si y o Technology
Chemni z, Ge many
[email p o ec ed]
Madhu Lakshman Myso e
Chai o Powe Elec onics
Chemni z Uni e si y o Technology
Chemni z, Ge many
[email p o ec ed]
Clemens He mann
Chai o Powe Elec onics
Chemni z Uni e si y o Technology
Chemni z, Ge many
[email p o ec ed]
Sudhanshu Goel
Robe Bosch GmbH
Reu lingen, Ge many
[email p o ec ed]
Ahmed Elsayed
Robe Bosch GmbH
Reu lingen, Ge many
[email p o ec ed]
Thomas Basle
Chai o Powe Elec onics
Chemni z Uni e si y o Technology
Chemni z, Ge many
[email p o ec ed]
Abs ac —The plasma densi y and dis ibu ion a e c ucial
ac o s in op imizing he e e se eco e y beha io o powe
semiconduc o de ices, pa icula ly unde condi ions o high
empe a u e and cu en densi y. This pape in es iga es he
impac o hyd ogen ion implan a ion du ing he manu ac u ing
p ocess o SiC enginee ed subs a es on he e e se eco e y
pe o mance o MOSFETs, compa ing hem o de ices based on
monoc ys alline subs a es. The esul s indica e a lowe e e se
eco e y cha ge, as e plasma o ma ion, and a educed cha ge
ca ie li e ime in he enginee ed subs a es. Elec o- he mal
simula ions u he suppo hese indings by demons a ing a
lowe ca ie densi y.
Index Te ms—SiC MOSFET, SiC enginee ed subs a e, body
diode, e e se eco e y, ca ie li e ime, TCAD
I. INTRODUCTION
The e e se eco e y cha ac e is ics o silicon ca bide (SiC)
MOSFETs a e c i ical o op imizing pe o mance, pa icula ly
in achie ing as , e icien swi ching wi h minimal losses.
Du ing he e e se eco e y phase, he deple ion o s o ed
cha ge accumula ed du ing he dead ime in oduces addi ional
losses, a ec ing bo h he ac i e and complemen a y swi ches.
Va ious ac o s in luence he e e se eco e y cha ge, in-
cluding mino i y ca ie li e ime, ope a ing empe a u e, and
load cu en . As empe a u e inc eases, he ioniza ion o p-
doped egions and he p olonged ca ie li e ime lead o
highe plasma densi y. These e ec s nega i ely impac e e se
eco e y pe o mance, esul ing in inc eased swi ching losses,
p onounced snappiness, and highe induced ol ages.
Op imizing plasma beha io is essen ial o minimize losses
and enhance e iciency and obus ness. A p o en me hod o
This wo k has been ca ied ou wi hin he Fas Lane p ojec . The p ojec is
suppo ed by he Chips Join Unde aking (JU) and i s membe s, including
op-up unding by Aus ia, F ance, Ge many, Romania, Slo akia, unde g an
ag eemen No 101139788.
silicon PIN diodes in ol es local li e ime con ol h ough
he in oduc ion o ecombina ion cen e s, which op imize
plasma dis ibu ion. Recen s udies sugges ha his app oach
is also applicable o silicon ca bide de ices [1] [2], esul ing
in imp o ed plasma dis ibu ion and a co esponding educ ion
in e e se eco e y cha ge. Howe e , his educ ion is accom-
panied by an inc ease in he on-s a e ol age d op.
A ecen s udy demons a ed a educ ion in e e se eco e y
cha ge wi hou impac ing on-s a e ol age d op by using SiC
enginee ed subs a es based on Sma Cu TM echnology [3].
The implan a ion o hyd ogen ions du ing he manu ac u ing
p ocess o bonded subs a es, which is used o spli he dono
wa e , leads o he o ma ion o poin de ec s ha educe he
e ec i e ca ie li e ime [5].
This s udy in es iga es plasma beha io as a unc ion o
cu en densi y, empe a u e, and dead ime. A no el me hod
o mo e accu a e de e mina ion o ca ie li e ime is p oposed.
Fu he mo e, elec o- he mal simula ions p o ide addi ional
insigh s in o he plasma beha io .
II. DEVICE STRUCTURE AND METHODOLOGY
SiC MOSFETs wi h a ol age class o 1200 V and a ench
s uc u e we e ab ica ed using a SiC enginee ed subs a e
based on Sma Cu TM echnology. This echnology combines
a hin, high-quali y monoc ys alline SiC laye wi h a hick,
low- esis i i y polyc ys alline SiC ca ie [4]. Fo compa ison,
e e ence SiC MOSFETs we e ab ica ed on a monoc ys alline
subs a e. Bo h ypes o SiC MOSFETs we e p ocessed unde
he same condi ions, ensu ing he same cell design, n-base
egion, and bu e laye . This enables he in es iga ion o he
subs a e’s impac on plasma beha io du ing e e se eco e y.
The measu ed s a ic C-V cha ac e is ics o he pa asi ic ca-
paci ances in he de ices a e shown in Fig.1. The capaci ances
demons a e simila ends wi h espec o he applied d ain-
sou ce ol age (VDS), indica ing ha he capaci i e swi ching
beha io emains compa able unde simila condi ions o bo h
echnologies.
0.1 1 10 100 1000
10p
100p
1 n
10n
C a p a c i a n c e [ F ]
VD S [ V ]
R e e e n c e
S i C e n g i n e e e d s u b s a e
Ci s s
Co s s
C s s
Fig. 1. Compa ison o he measu ed C-V cha ac e is ic o bo h echnologies.
The e e se eco e y beha io o he body diode in he
SiC MOSFET was in es iga ed using a double-pulse se up.
Bo h he high-side and low-side swi ches u ilized he same
ype o MOSFET. The DC-link ol age (VDC) was adjus ed o
800 V, and he ga e-sou ce ol age (VGS) was se o −10 V o
elimina e he in luence o he n-channel du ing he dead ime
( dead). A dead ime o 1 µs was selec ed o ensu e comple e
plasma o ma ion.
Measu emen s we e conduc ed a cu en densi ies eaching
up o h ee imes he nominal alue and empe a u es up o
200°C. A coaxial shun was used o cu en measu emen ,
while ol age was measu ed using a passi e p obe connec ed
o a sepa a e oscilloscope. Fig. 2 shows he esul s ob ained a
maximum cu en densi y o bo h echnologies.
The e e se eco e y cha ge (QRR) was de e mined acco d-
ing o JEDEC JEP201 s anda ds (see Fig. 2). The de e mined
QRR consis s o capaci i e s o ed cha ge (QC) and s o ed
cha ge om cha ge ca ie s (QPlasma). The capaci i e cha ge
is de i ed om he de ice’s ou pu capaci ance Qoss, de e -
mined by he Coss(V) cu e (Fig. 1) and he applied VDC.
Addi ionally, he pa asi ic capaci ance o he load induc ance
− 8 0 − 4 0
0 40 80 120 160
− 0 . 8
− 0 . 4
0 . 0
0 . 4
0 . 8
1 . 20
250
500
750
1000
1250
1500
jS ( D i o d e ) [ k A / c m ² ]
i m e [ n s ]
di / d = - 5 k A / µ s
c 1
e x a c i o n o QR R
VD S ( D i o d e ) [ V ]
R e e e n c e
S i C e n g i n e e e d s u b s a e
9 8 % VD C
Fig. 2. Compa ison o he e e se eco e y beha io a VDS = 800 V,
jS= 1 kA/cm², VGS =−10 V, dead = 1 µs, and T j = 200°C.
and he es ci cui con ibu es u he o QC. To accu a ely
quan i y QC, measu emen s we e conduc ed du ing he ini ial
pulse o he double-pulse es acco ding o JEDEC JEP201
[6], ensu ing no bipola cha ge componen in he absence o
cu en . A QCo 325 nC was de e mined o he e e ence
de ice and 328 nC o he SiC enginee ed subs a e based
de ice.
III. EXPERIMENTAL RESULTS AND DISCUSSION
A. Plasma S o ed Cha ge
The plasma s o ed cha ge was ini ially analyzed as a unc-
ion o cu en densi y and empe a u e o bo h echnologies.
Fig. 3 illus a es he empe a u e dependence o QPlasma, co -
ec ed by he p e iously men ioned QC, a nominal and h ee
imes he nominal cu en densi y.
20 40 60 80 100 120 140 160 180 200 220
0 . 0
0 . 4
0 . 8
1 . 2
1 . 6
2 . 0
2 . 4 R e e e n c e
S i C e n g i n e e e d s u b s a e
QP l a s m a [ µ C ]
T e m p e a u e [ ° C ]
44%
30%
jnom
3x jnom
Fig. 3. Plasma s o ed cha ge (QPlasma) as a unc ion o empe a u e (T) o
di e en cu en densi ies (j) a VDS = 800 V, VGS =−10 V, and dead = 1 µs.
In gene al, QPlasma inc eases wi h empe a u e due o he
highe ioniza ion deg ee o he p-doped egions and he
enhanced e ec i e ca ie li e ime (τe ). Howe e , he inc ease
obse ed in he de ice based on he SiC enginee ed subs a e is
smalle , esul ing in a lowe QPlasma compa ed o he e e ence.
This di e ence becomes mo e p onounced wi h inc easing
empe a u e and cu en densi y. Mo eo e , a signi ican in-
c ease in QPlasma o he SiC enginee ed subs a e based de ice
is only obse ed a empe a u es abo e 100°C.
Since QPlasma is di ec ly p opo ional o bo h cu en and
e ec i e ca ie li e ime, he obse ed educ ion in QPlasma
o he SiC enginee ed subs a e based de ice unde iden ical
es condi ions can be a ibu ed o a lowe e ec i e ca ie
li e ime.
B. Dead Time Dependency
A deepe unde s anding o he plasma o ma ion p ocess
du ing o wa d eco e y in bo h echnologies can be gained
by analyzing he ela ionship be ween he e e se eco e y
cha ge and he dead ime. Fig. 4 shows he a io o QRR o QC
as a unc ion o dead ime a he nominal cu en densi y and
a h ee imes he nominal alue, measu ed a a T j o 200°C.
Plasma o ma ion occu s wi h a lowe ime cons an o he
SiC enginee ed subs a e, e e ed o as he o wa d eco e y
ime cons an (τFR), compa ed o he e e ence de ice. A h ee
imes he nominal cu en , τFR is educed by 33% o he
100 1000 10000
3
4
5
6
7
8
QRR/QC
d e a d [ n s ]
R e e e n c e
S i C e n g i n e e e d s u b s a e
Fig. 4. Ra io o QRR o QCas a unc ion o dead ime ( dead) o di e en
cu en densi ies a T j = 200°C.
SiC enginee ed subs a e based de ice, esul ing in plasma
sa u a ion a sho e dead imes. A nominal cu en densi y,
he di e ence is less p onounced.
Plasma sa u a ion du ing o wa d eco e y is achie ed only
when an equilib ium be ween cha ge ca ie gene a ion and
ecombina ion is eached. This p ocess is in luenced by he
ca ie li e ime and emi e e iciency, wi h a sho e ca ie
li e ime leading o as e plasma sa u a ion.
Hence, he as e plasma sa u a ion obse ed in he SiC
enginee ed subs a e based de ice is p ima ily a ibu ed o
a lowe ca ie li e ime.
C. Ca ie Li e ime
The obse ed educ ion in QPlasma and he as e plasma
o ma ion in he SiC enginee ed subs a e based de ice com-
pa ed o he e e ence de ice indica e a s ong dependence on
ca ie li e ime. The e ec i e ca ie li e ime τe , de e mined
om he ela ionship be ween QPlasma and load cu en , anges
om 10–15 ns o he e e ence de ice and 5–10 ns o he SiC
enginee ed subs a e based de ice, based on he measu emen s
in Fig. 3. Thus, τe is lowe o he SiC enginee ed subs a e
based de ice. Howe e , his alue is unde es ima ed compa ed
o he expec ed ca ie li e ime in conduc ion mode due o
su ace ecombina ion e ec s. Mo eo e , τe p ima ily e lec s
he ca ie li e ime in he hea ily doped emi e egion, making
i signi ican ly sho e han he bulk ca ie li e ime in he
ligh ly doped egion [7].
To p opose an addi ional app oach o e alua ing he ca ie
li e ime, simila o he open-ci cui ol age decay (OCVD)
me hod, he beha io o VSD is analyzed du ing he ansi-
ion om bipola o unipola cu en conduc ion in he hi d
quad an , i.e., du ing plasma deple ion. Fo his pu pose, he
de ice is con inuously ope a ed unde a cons an cu en (also
o a oid di/d e ec s in luencing he measu emen ), while he
ga e ol age is swi ched be ween VGS = 18 V (channel open -
unipola mode) and −10 V (channel closed - bipola mode).
Fig. 5 shows he beha io o VSD du ing he ansi ion
om bipola o unipola ope a ion o bo h echnologies a a
empe a u e o 150°C and app oxima ely he nominal cu en
densi y. Fo he e e ence de ice, a sligh ly highe cu en
densi y was equi ed o achie e he same de ice empe a u e.
An exponen ial unc ion was i ed o he ol age wa e o m o
ex ac he cha ge decay ime cons an (τCD).
The SiC enginee ed subs a e based de ice exhibi s a as e
cha ge decay, as indica ed by a as e ol age ise, wi h τCD
being 40% smalle han ha o he e e ence de ice. This
aligns wi h a 37% dec ease in QPlasma unde compa able
condi ions (see Fig. 3). The educed ol age d op in unipola
mode is a ibu ed o he lowe esis ance o he highly doped
poly-SiC laye [3].
0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5 3 . 0 3 . 5
0 . 8
1 . 0
1 . 2
1 . 4
1 . 6
1 . 8
2 . 0
− 1 2
− 8
− 4
048
1 2
1 6
2 0
0 . 0
0 . 2
0 . 4
0 . 6
0 . 8
VS D [ V ]
i m e [ µ s ]
τ
C D
≈
4 1 5 n s
τ
C D
≈
6 9 5 n s
e x p o n e n i a l i
jS [ k A / c m ² ]
VG S [ V ]
R e e e n c e
S i C e n g i n e e e d s u b s a e
u n i p o l a b i p o l a
Fig. 5. Fo wa d ol age d op du ing he ansi ion om bipola o unipola
hi d quad an DC cu en conduc ion o bo h echnologies a app ox. nominal
cu en densi y, wi h T j = 150°C, and VGS =+18 V/−10 V.
D. Elec o-The mal Simula ion Resul s
To analyze he plasma dis ibu ion wi hin he de ice based
on subs a e echnology and i s impac on e e se eco e y
cha ge educ ion, elec o- he mal simula ions we e pe o med
using Synopsys TCAD [8]. A hal -cell 1200 V SiC MOSFET
wi h a ench cell s uc u e was u ilized o ep oduce he
undamen al beha io . The subs a e-speci ic cha ac e is ics
we e inco po a ed by in oducing li e ime-killing aps in he
bonded mono SiC laye and adjus ing he doping densi y o
he poly SiC laye as desc ibed in [3].
The e e se eco e y beha io o bo h echnologies was
ini ially simula ed a h ee imes he nominal cu en densi y
and a empe a u e o 200°C, using dead imes o 100 ns and
1000 ns. As shown in Fig. 6, longe dead imes esul in highe
e e se eco e y cu en peaks and longe eco e y imes o
bo h subs a es, consis en wi h measu emen s. Howe e , he
o al cha ge is lowe in he SiC enginee ed subs a e based
de ice compa ed o he e e ence de ice, which aligns wi h
expe imen al measu emen s (see Fig. 4).
Plasma o ma ion in bo h subs a e echnologies was exam-
ined by analyzing elec on and hole dis ibu ion a a ious ime
poin s wi hin a 1 µs dead ime. As shown in Fig. 7, ime poin
1ma ks he onse o bipola cu en conduc ion.
A 1, he SiC enginee ed subs a e de ice exhibi s a sligh ly
highe elec on densi y in he d i egion compa ed o he
e e ence, which is a ibu ed o inc eased doping om he
poly-SiC laye . This enhances elec on injec ion and inc eases
he ini ial hole densi y. A e 50 ns ( 2), he ca ie densi y nea
he p- egion become simila o bo h subs a es. Howe e , he
− 8 0 − 6 0 − 4 0 − 2 0
0 2 0 4 0 6 0 8 0 1 0 0
− 0 . 8
− 0 . 4
0 . 0
0 . 4
0 . 8
1 . 20
250
500
750
1000
1250
1500
jS ( D i o d e ) [ k A / c m ² ]
i m e [ n s ]
VD S ( D i o d e ) [ V ]
R e e e n c e
S i C e n g i n e e e d s u b s a e
d e a d :
1 0 0 n s
1000 ns
Fig. 6. Compa ison o he simula ed e e se eco e y beha io a h ee
imes he nominal cu en densi y o di e en dead imes a VDS = 800 V,
VGS =−10 V, and Tj= 200°C.
1 E 1 0
1 E 1 2
1 E 1 4
1 E 1 6
1 E 1 8
1 E 2 0
1 E 1 4
1 E 1 6
1 E 1 8
1 E 2 0
h o l e d e n s i y [ c m - 3 ]
C h i p h i c k n e s s [ a . u . ]
1 = 0 µ s 2 = 0 . 0 5 µ s 3 = 0 . 2 µ s
4 = 0 .3 µ s 5 = 1 µ s
e l e c o n d e n s i y [ c m - 3 ]
p - e g i o n d i e g i o n b u e s u b s a e
R e e e n c e
S i C e n g i n e e e d s u b s a e
l i e i m e
k i l l i n g a p s
Fig. 7. Compa ison o he elec on and hole densi y o di e en ime poin s
a h ee imes he nominal cu en densi y, wi h VGS =−10 V,Tj= 200°C,
and dead = 1 µs.
SiC enginee ed subs a e de ice shows a lowe ca ie densi y
owa d he bu e due o he li e ime-killing e ec , esul ing
in a educed pene a ion dep h. Hyd ogen ion implan a ion
in o he mono-SiC laye , ollowed by annealing, inc eases
he concen a ion o Z1/2 and o he ecombina ion cen e s,
which educe elec on li e ime and limi ca ie injec ion [5].
Consequen ly, he hole densi y dec eases, pa icula ly a he
d i /bu e in e ace. Du ing o wa d eco e y, he elec on
and hole densi ies in he d i egion con inue o inc ease.
Fig. 8 shows he hole dis ibu ion in he d i egion a di e en
ime poin s o bo h echnologies o imp o e isibili y.
The hole concen a ion sa u a es ea lie in he SiC engi-
nee ed subs a e based de ice compa ed o he e e ence. In he
e e ence de ice, sa u a ion occu s a e 350 ns, whe eas in he
SiC enginee ed subs a e based de ice, i occu s a e 250 ns.
This ea lie sa u a ion is a ibu ed o he lowe e ec i e ca ie
li e ime and he lowe emi e e iciency. These indings align
well wi h he measu emen s shown in Fig. 4.
Acco ding o he ade-o be ween plasma densi y and
ol age d op in bipola de ices, MOSFETs based on SiC
enginee ed subs a es a e expec ed o exhibi a highe ol age
d op in he hi d quad an du ing bipola ope a ion due o he
3 E 1 6
4 E 1 6
5 E 1 6
6 E 1 6
7 E 1 6
8 E 1 6
9 E 1 6
1 E 1 7
8 E 1 6
8 . 4 E 1 6
8 . 8 E 1 6
9 . 2 E 1 6
9 . 6 E 1 6
1 E 1 7
h o l e d e n s i y [ c m - 3 ]
C h i p h i c k n e s s [ a . u . ]
1 = 0 . 1 0 µ s 2 = 0 . 1 5 µ s 3 = 0 . 2 0 µ s
4 = 0 . 2 5 µ s 5 = 0 . 3 0 µ s 6 = 1 µ s
1 = 0 . 1 5 µ s 2 = 0 . 2 0 µ s 3 = 0 . 2 5 µ s
4 = 0 . 3 0 µ s 5 = 0 . 3 5 µ s 6 = 1 µ s
S i C e n g i n n e e d s u b s a e
R e e e n c e
h o l e d e n s i y [ c m - 3 ]
Fig. 8. Compa ison o hole densi y in he d i egion a h ee imes he
nominal cu en , wi h VGS =−10 V,Tj= 200°C, and dead = 1 µs.
lowe plasma densi y. Elec os a ic po en ial analysis in Fig. 9
con i ms his expec a ion in he d i egion, bu e , and he
ini ial mic ome e s o he subs a e. Howe e , he p esence o a
highly doped poly-SiC subs a e compensa es o he inc eased
ol age d op in hese egions. Consequen ly, he o e all ol age
d op VSD is educed om 3.55 V o 3.3 V a gi en condi ions.
Elec os a ic
Po en ial [V]
-1.2
-1.3
-1.4
-1.5
-1.6
-1.7
-1.8
p- egion d i egion bu e subs a e
Re e ence
SiC enginee ed
subs a e
−1.3
−1.4
−1.5
−1.6
−1.7
−1.8
Elec os a ic Po en ial [V]
Chip hickness [a.u.]
Re e ence
SiC enginee ed subs a e
subs a e
d i
egion
bu e
Fig. 9. Compa ison o elec os a ic po en ial a h ee imes he nominal
cu en , wi h Tj= 200°C, VGS =−10 V, and dead = 1 µs.
IV. CONCLUSION
The e e se eco e y beha io and plasma o ma ion o
SiC MOSFETs ab ica ed on enginee ed subs a es we e in-
es iga ed h ough measu emen s and elec o- he mal TCAD
simula ions. Compa ed o SiC MOSFETs on monoc ys alline
subs a es, hese de ices exhibi a signi ican educ ion in
plasma cha ge, which becomes mo e p onounced wi h inc eas-
ing empe a u e and cu en densi y. Fu he mo e, he cha ge
measu emen s as a unc ion o dead ime indica e a as e
plasma o ma ion beha io . The ex ac ed ca ie li e ime is
lowe and iden i ied as one o he p ima y causes o his
beha io . Elec o- he mal simula ions e eal a educed ca ie
densi y, pa icula ly a he in e ace be ween he d i egion
and he bu e .
REFERENCES
[1] P. Hazd a, S. Popelka and A. Sch¨
one , ”Op imiza ion o SiC Powe p-
i-n Diode Pa ame e s by P o on I adia ion”, in IEEE T ansac ions on
Elec on De ices, ol. 65, no. 10, pp. 4483-4489, Oc . 2018.
[2] K. Konishi, N. Wa anabe, H. Okino, Y. Mo i, A. Shima, ”E ec s o
P o on I adia ion be o e De ice Fab ica ion on he Swi ching Cha ac-
e is ics o 3.3 kV SiC MOSFETs”, in P oc. ICSCRM 2024, Raleigh,
USA, 2024.
[3] M. Alaluss e al., ”Dynamic Cha ac e iza ion and Robus ness o SiC
MOSFETs based on Sma SiCTM enginee ed subs a es”, in P oc. IC-
SCRM 2024, Raleigh, USA, 2024.
[4] S. Rouchie e al., ”150 mm SiC enginee ed Subs a es o High-Vol age
Powe De ices” Ma e ials Science Fo um, ol. 1062, pp. 131-135, 2022.
[5] H. Uchida e al., ”Analysis o T ap Cen e s Gene a ed by Hyd ogen
Implan a ion in 4H-SiC Bonded Subs a es”, in P oc. ICSCRM 2024,
Raleigh, USA, 2024.
[6] JEDEC ”Guidelines o Re e se Reco e y Time and Cha ge Measu e-
men o SiC MOSFET” in JEDEC JEP201, Aug. 2024.
[7] T. Kimo o and J. A. Coope , ”Fundamen als o Silicon Ca bide Technol-
ogy: G ow h, Cha ac e iza ion, De ices, and Applica ions”. Wiley-IEEE
P ess, 2014. DOI: 10.1002/9781118313534.
[8] Synopsys Inc., ”TCAD Sen au us Manual”, Moun ain View, CA, USA,
2022.
