De ec o De elopmen o Pa icle Physics
Simon Waid , J¨
u gen Maie , Philipp Gaggl, And eas Gspone , Pa ick Siebe e ,
Maximilian Babeluk, Thomas Be gaue
Aus ian Academy o Sciences,Ins i u e o High Ene gy Physics,Vienna, Aus ia
E-Mail: [email protected] , homas.be gaue @oeaw.ac.a
Abs ac —In high ene gy physics expe imen s, acking and
e exing is nowadays mos ly done using semiconduc o de ec-
o s. Among he employed de ec o s a e hyb id pixel senso s,
passi e senso s and ecen ly also deple ed monoli hic ac i e pixel
senso s (DMAPS), which in eg a e he pa icle senso wi h on -
end elec onics. The dominan ma e ial o he p oduc ion o such
senso s cu en ly is silicon. Howe e , he use o silicon ca bide
is cu en ly being in es iga ed. In his wo k we epo on ou
p og ess on he de elopmen o silicon based DMAPS. Fu he ,
we p esen a no el on -end ci cui o passi e silicon ca bide
de ec o s.
Index Te ms—beam moni o , high ene gy, de ec o , senso ,
silicon ca bide, asic, cmos, adia ion ha dness, ionizing adia ion,
maps, dmaps, s ip senso
I. INTRODUCTION
Pa icle de ec o s ha e e ol ed o e decades. While a i s
pa icle acks we e eco ded using cloud chambe s, se e al
echnologies ha e eplaced hem since hen. One o he main
d i e s o his de elopmen has been he sea ch o a e e en s
equi ing he as eco ding o e en s. Up o now his is
a ained by high spacial accu acy and disc imina ion o acks
based on he loca ion o he collision. Cu en ly, esea ch
is mo ing owa ds in oducing empo al disc imina ion o
pa icle acks. To a ain highes spacial accu acy as well
as enable as eadou and s o age o eco ded in o ma ion,
semiconduc o based de ec o s a e employed. Among hem
a e hyb id pixel senso s (HPS), passi e senso s and deple ed
monoli hic ac i e pixel senso s (DMAPS).
In HPS he sensing elemen and he eadou elec onics a e
p ocessed on sepa a e subs a es and hen bonded oge he .
They p o ide a la ge lexibili y in e ms o p ocessing o
he adia ion sensing elemen and hus o e he highes
pe o mance. Howe e , p ocessing senso and eadou ci cui
sepa a ely and bonding hem oge he a e wa ds inc eases
p ocess complexi y which educes yield and eliabili y. S ill,
due o hei supe io pe o mance HPS a e cu en ly he domi-
nan echnology o acking in pa icle collision expe imen s.
They a e employed in he acke o he CMS, ATLAS and he
BELLE-2 expe imen . Cu en ly, his dominance is challenged
by a new gene a ion o deple ed monoli hic pixel senso s
(DMAPS). DMAPS in eg a e he sensing elemen and eadou
The au ho s ecei ed unding om he Aus ian Resea ch P omo ion
Agency FFG (P ojec N . 883652 and 878691) and he Eu opean Union
(P ojec AIDAinno a G an ag eemen ID: 101004761).
elec onics in o he same die. This educes he manu ac u ing
complexi y, cos and ma e ial budge . Gi en hei ad an ages,
DMAPS can be expec ed o eplace HPS in mos applica ions.
A an inc eased dis ance om he collision poin (a e
he acke ) he e ex de ec o is loca ed. He e, ATLAS,
BELLE-2 and CMS employ passi e s ip de ec o s. These
ha e signi ican ly lowe manu ac u ing cos s han MAPS o
HPS. Due o hei simplici y, hey addi ionally o e a high
manu ac u ing yield and can co e la ge a eas. Howe e , due
o he desi e o inc easing occupancy in expe imen s, he e is
ongoing wo k o eplace he s ip de ec o s wi h pixel senso s.
Signi ican R&D e o is in es ed a he momen o imp o e
DMAPS, since i can be expec ed ha hese will e en ually
eplace bo h HPS and passi e s ip senso s in many applica-
ions. One example is he BELLE-2 VXD upg ade, whe e he
op imized Belle II pixel senso (OBELIX) DMAPS is one o
he candida e de ec o s o eplacing bo h he pixel de ec o
and he silicon e ex de ec o wi h one uni ied de ec o [1].
In ega d o subs a e ma e ials, silicon is cu en ly dominan
o semiconduc o de ec o s. I s main ad an ages a e he a ail-
abili y o low cos wa e s and high pe o mance semiconduc o
p ocesses. Howe e , om a physical pe spec i e silicon is no
an ideal de ec o ma e ial since, o example, he da k cu en
a oom empe a u e is high. This ende s he de ec ion o
small signals a challenging ask. Thus, al e na i es a e unde
in es iga ion, whe eas silicon ca bide is (SiC) a e y p omising
candida e [2]. SiC is cu en ly being adop ed by an inc easing
numbe o semiconduc o companies such ha high quali y
subs a es a e a ailable a mode a e cos s. Fu he mo e, mo e
and mo e ound y se ices o such subs a es a e becoming
a ailable. As a de ec o , compa ed o silicon, SiC p omises
be e ime esolu ion due o i s la ge sa u a ion eloci y
(200 µm ns−1 e sus 100 µm ns−1 o Si) [3]. Fu he , due
o i ’s low leakage cu en s a e exposu e o adia ion, i
p omises o educe powe consump ion [3], [4]. As a con-
sequence, SiC is cu en ly gaining subs an ial a en ion om
he esea ch communi y.
In his wo k we p esen ou con ibu ion o he de elopmen
o silicon DMAPS as well as a no el eadou on end o
SiC de ec o s. In he ealm o DMAPS we ha e con ibu ed
o he end o column (EOC) ci cui o he RD50-MPW3 ASIC.
Fu he , we a e wo king on he on-chip da a p ocessing in he
Op imized Belle II pixel senso (OBELIX) gea ed owa ds
Belle 2 expe imen . In he ealm o silicon ca bide we a e
wo king on a p ima y beam moni o consis ing o passi e
SiC s ip de ec o s. Fo he eadou o SiC s ip de ec o s we979-8-3503-5785-1/23/$31.00 ©2023 IEEE
40
2023 Aus ochip Wo kshop on Mic oelec onics (Aus ochip) | 979-8-3503-5785-1/23/$31.00 ©2023 IEEE | DOI: 10.1109/Aus ochip61217.2023.10285161
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p esen an op imized ansimpedance ampli ie (TIA) ci cui .
II. DEPLETED MONOLITHIC PIXEL SENSORS (DMAPS)
A. RD50-MPW3
The DMAPS senso de eloped wi hing he RD50 collab-
o a ion is implemen ed in he L ound y 150 nm (LF15A)
p ocess. The senso uses a ully deple ed subs a e o pa icle
de ec ion. The deple ion is a ained by applying a high ol age
be ween he on side elec onics and a backside elec ode
a ached o he hinned-down subs a e. Cha ge collec ion is
pe o med using he la ge collec ion elec ode app oach. The
deple ion zone is isola ed om he eadou elec onics ia a
deep n-well (DNWELL) which is one o he unique ea u es
o he LF15A p ocess [5].
The pixel size o he chip is 62 x 62 µm2. The ou pu o a
la ge collec ion elec ode is ampli ied using a cha ge sensi i e
ampli ie and shaped. A compa a o is used o de ec a pa icle
ansi ion. In he case o such an e en he s a us o he
global clock is s o ed in he in-pixel andom access memo y
(RAM) o enable ime s amping and ime-o e - h eshold (ToT)
measu emen s. Pixels a e ead ou ia a sha ed column bus,
whe eas he in-pixel logic enables pixel masking o p e en
dead pixels om blocking he column bus. Each column has
an EOC ci cui in which e en s a e s o ed and made a ailable
o eadou ia a wishbone bus. The ime esolu ion o he
applica ion speci ic in eg a ed ci cui (ASIC) is 40 ns [6].
B. OBELIX
The OBELIX senso is implemen ed in he Towe Jazz
180 nm p ocess. In con as o he RD50-MPW3 ASIC he
design u ilizes a small collec ion elec ode. The OBELIX
senso is one o ou p oposals o he (pa ial) eplacemen
o he VTX de ec o o he BELLE-2 expe imen . OBELIX is
de i ed om he exis ing TJ-Monopix2 chip. The senso will
ea u e a pixel pi ch be ween 30 µm o 40 µmand a imes amp
accu acy o 25 ns. In con as o TJ-Monopix2, OBELIX will
ha e a igge ed eadou a chi ec u e enabling a igge a e o
up o 30 kHz. [1]
III. MOVING FROM SILICON TO SILICON CARBIDE
A. Silicon Ca bide (SiC) Pa icle Senso s
SiC has he a o able p ope y ha i ’s da k cu en does no
subs an ially inc ease a e an exposu e o ionizing adia ion.
Measu emen s o 3 x 3 mm2SiC de ec o pads, which we e
i adia ed by neu on luences o up o 1016 neq/cm2[7]
e eal, ha he da k cu en emains below 1 pA mm−2in
all cases. A compa ison o he cu en spike gene a ed by
when a single pa icle passes h ough he de ec o (a leas
0.5µA) shows, ha he da k cu en is negligible e en o
la ge de ec o a eas. Consequen ly, he eadou ci cui does no
need a cu en compensa ion when accessing he de ec o . This
lowe s he losses in he de ec o , educes he cooling demands
and enables, i desi ed, a DC coupling be ween de ec o and
eadou ci cui .
This p ope y e en enables he de elopmen o senso s ha
can de ec bo h single pa icles and pa icle luxes, whe e
single pa icles can no be disc imina ed anymo e. We a e
aiming o deploy such a de ice a Medaus on, a cance
ea men cen e , which p o ides a ious pa icle a es: In
he kHz ange pa icle de ec o es s a e un, whe eas single
pa icle coun ing is ealized by de ec ing cu en spikes. Ra es
in he GHz ange a e used o pa ien ea men and biological
esea ch and demand DC coupled measu emen s. Beams in
he THz ha e al eady been demons a ed and migh become
a ailable o esea ch in he nea u u e. The beam moni o s
cu en ly in ope a ion a e only able o ope a e in one o he
wo lowe egimes, while he no el SiC based moni o s will
be able o handle bo h simul aneously.
Due o p ocess limi a ions, i.e., he absence o ad anced
complemen a y me al-oxide-semiconduc o (CMOS) p ocess-
ing op ions, SiC is s ill es ic ed o passi e senso s, e.g.,
s ip de ec o s, o HPS. Ne e heless, sui able p ocesses, o
example he dedica ed p ocess o SiC de ec o s de eloped by
[8], a e al eady a ailable. I consis s o a single p-implan in o
he n-subs a e and a single me al laye . Consequen ly only
i e masks a e equi ed, leading o low cos s o p o o ype
p oduc ion. Toge he wi h CNM we ha e designed se e al es
ehicles o adia ion ha dness s udies and nume ous p o o ype
s ip de ec o s o ou beam moni o .
B. SiC Senso Readou
Commonly de ec o s a e ead by u ilizing a cha ge sensi i e
ampli ie s (CSA) in he inpu s age, which, howe e , limi he
a ailable bandwid h. This is p oblema ic o a SiC de ice as
he high sa u a ion eloci y leads o a cu en pulse du a ion
o only 0.4 ns pe pa icle on a 100 µm hick senso . Con-
sequen ly, we swi ched o a ansimpedance ampli ie (TIA)
based eadou on -end op imized o SiC s ip de ec o s.
Gi en he limi a ions o p ocessing echnology a ailable o
SiC, he TIA is implemen ed on silicon.
We chose a TIA design based on he “in e e wi h ac i e
common-d ain eedback” (ICDF) ci cui p esen ed in [9].
Compa ed o he adi ional egula ed cascode (RGC)-TIA
ci cui , he ICDF has a la ge gain in he eedback pa h.
This educes he inpu impedance and supp esses noise. A
simila app oach was used in [10], whe e he ampli ica ion
was imp o ed by in oducing wo cascodes in he in e e .
The TIA (ci cui le el implemen a ion shown in Fig. 1) was
implemen ed in a 130 nm silicon CMOS p ocess (Skywa e
SKY130A). T ansis o sizes a e p o ided in Table I. Ou
design goal was o achie e a su icien bandwid h o de ec ing
he expec ed cu en pulses om a 100 µm hick SiC senso
(a leas 1.2 GHz o e all empe a u es and co ne s) while
simul aneously minimizing noise and inpu impedance.
To a ain hese design goals, a combina ion o he ci cui s
gi en in [9] and [10] was implemen ed. Compa ed o [10]
he smalle p ocess node made he addi ion o wo cascode
ansis o s o he in e e un a ou able. Ins ead, only one
cascode was in oduced o he n-channel pa o he in e e ,
while he cascode was omi ed o he p-mos ansis o . When
connec ing he ga e o he cascode ansis o s di ec ly o VDD
and GND, as shown in [10], simula ions e ealed ha p ocess
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VN
VP
Ou 2
Bias1
Inpu
Ou 1
Bias2
M2
S
D
BG
LVT
M4
D
S
BG
M6
S
D
BG
LVT
M1
S
D
B G
LVT
M5
S
D
BG
LVT
R1
B
M3
S
D
BG
LVT
Fig. 1: Schema ic o he TIA. The ci cui combines elemen s
o he ci cui s p esen ed in [9] and [10]. Simila ly o [10],
he ICDF p esen ed in [9] was augmen ed by one cascode
ansis o in he in e e . In con as o [10] o he used p ocess
node only one cascode ansis o is mo e a o able han wo.
VN
VP
Ou _ e
Bias3
Bias1
Bias2
M2B
S
D
BG
LVT
M4B
D
S
BG
M6B
S
D
BG
LVT
M1B
S
D
B G
LVT
M5B
S
D
BG
LVT
R1B
B
M8
S
D
BG
LVT
M7
S
D
BG
LVT
M3B
S
D
BG
LVT
C1
M9
D
S
BG
M10
D
S
BG
Fig. 2: Biasing ci cui o he cascode ansis o and second
copy o he TIA. The biasing ci cui coun e s he impac o
empe a u e and p ocess a ia ions. The second copy o he
TIA p o ides a e e ence ol age o he ou pu di e en ial
ampli ie enabling DC cu en measu emen s.
a ia ions cause signi ican changes. To supp ess his e ec we
in oduced a biasing ci cui (see Fig. 2), which, unde ypical
condi ions se s he ga e ol age almos o VDD. Fo cases
wi h low h eshold ol ages, howe e , he ans e se cu en
h ough he in e e is limi ed. The chosen sizes a e again
gi en in Table I.
The TIA ea u es wo ou pu s: Ou 1 and Ou 2 (c . Fig. 1).
The au ho s in [9] used Ou 1 as he signal was la ge , howe e ,
in ou case Ou 2 u ned ou as he op imal one. We chose o
TABLE I: T ansis o Dimensions
T ansis o Wid h Leng h T ansis o Wid h Leng h
/ µm/ µm/ µm/ µm
M1, M1B 120 0.15 M6, M6B 240 0.15
M2, M2B 360 0.15 M7 14 0.15
M3, M3B 80 0.15 M8 40 0.15
M4, M4B 80 0.15 M9 240 0.5
M5, M5B 240 1 M10 240 0.15
employ R1 as ansimpedance de e mining elemen ins ead o
a ansis o as done in [9] and [10]. While a ansis o p omises
o inc ease he usable bandwid h, p ecision esis o s educe he
p ocess dependence o he ans-impedance. Since ou design
is no p ima ily op imized o bandwid h and he use o a
esis o did no esul in any educ ion o bandwid h, we op ed
o his a ian . The chosen alue o R1 was 1.9 kΩ.
We also in end o measu e DC cu en s. Fo his pu pose
a copy o he TIA was implemen ed. The copy p o ides he
ou pu ol age o he TIA when no inpu cu en is applied. A
se ies o di e en ial ampli ie s is used o ma ch he signal o
he in ended ou pu impedance o 50 Ω. Simila ly o [9], he
di e en ial ampli ie chain has 3 s ages. I adds up o 10 dB
o gain o he TIA and has a nominal ou pu impedance o
50 Ω. The copy o he TIA was in eg a ed oge he wi h he
biasing ci cui and is shown in Fig. 2. The TIA ou pu o he
inpu o he di e en ial ampli ie is gi en a Ou e . The Bias
ol age o he main TIA is p o ided a Bias2.
The o e all layou is shown in Fig. 3. Pos layou simula-
ions o he TIA show ha he a ained bandwid h will be
be ween 1.2 and 1.8 GHz depending on p ocess a ia ions
and empe a u e. Fo equencies up o 1.2 GHz he inpu
impedance is below 40 Ω o all empe a u es. Thus, an inpu
capaci ance o up o 3 pF can be pe mi ed. Fo he uppe
bound he inpu e e ed noise as a unc ion o equency
is shown in Fig. 4. Below 1.2 GHz i is below 30 pA/√Hz,
while a minimum o 10 pA/√Hz is achie ed o equencies
be ween 10 MHz and 200 MHz.
IV. CONCLUSION
We ha e epo ed on ou ac i i ies on he de elopmen
o pa icle de ec o s. In he domain o DMAPS we ha e
con ibu ed he EOC ci cui o he RD50-MPW3 ASIC and
a e cu en ly wo king on he on-chip digi al p ocessing ci cui
o he OBELIX pixel senso .
Gi en he a ac i e p ope ies o SiC as a de ec o ma e ial
we a e wo king on SiC based de ec o s. As a i s applica ion
we a e using SiC o a p ima y beam moni o . In his speci ic
applica ion SiC ou pe o ms Si due o i negligible da k cu en
e en i exposed o adia ion. In ou case, de ec o s can ole a e
luences o up o 1016 neq/cm2while s ill main aining da k
cu en le els 3 o de s o magni ude smalle han he signal
gene a ed by pa icles.
We de eloped an analog on -end o eading ou SiC s ip
de ec o s. In con as o he commonly applied CSA on -
end, we chose o implemen a TIA o ampli ying he signals
om he de ec o . We expec he de ec o o emi pulses o
app ox. 0.4 ns and hus op imized he bandwid h o he TIA
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Biasing
Re .
TIA
Ou pu
d i e
TIA
Fig. 3: GDS layou o wo TIA channels. One biasing ci cui
supplies bo h channels. Each TIA channel is composed o wo
copies o he TIA and a di e en ial ou pu d i e . One o wo
TIAs is a ached o he de ec o , while he o he p o ides a
ze o-cu en ou pu ol age as e e ence o he di e en ial
ou pu d i e . The submi ed chip con ains 9 imes 2 channels
o aling o 18 channels wi h an a e age channel pi ch o 250µm
ma ched o a SiC s ip de ec o .
Fig. 4: Pos layou simula ion o he inpu e e ed noise o he
implemen ed TIA. The inpu was loaded wi h a 3 pF capaci o .
The noise is below 30 pA/√Hz o equencies up o 1.2 GHz
wi h a minimum o 10 pA/√Hz be ween 10 MHz and 200
MHz.
o a bandwid h o 1.2 GHz. Due o i ’s low inpu impedance
we chose a ICDF-TIA opology o he TIA. Fo equencies
up o 1.2 GHz, he TIA exhibi s an inpu impedance o 40 Ω.
We expec he TIA o be loaded wi h a de ec o capaci ance
o up o 3 pF. When loaded wi h a 3 pF de ec o , he noise is
below 30 pA/√Hz o equencies up o 1.2 GHz. I eaches
a minimum o 10 pA/√Hz be ween 10 MHz and 200 MHz.
A compa ison o o he ICDF-TIAs is gi en in able II.
Fig. 5: Inpu impedance i he TIA. The inpu impedance
is below 40 Ω o equencies up o 1.2 GHz o all p ocess
co ne s and o e he ull ope a ing empe a u e ange.
TABLE II: Compa ison o ICDF-TIAs
Re e ence [10] [9] This wo k
BW / GHz 6 7 1.2
Noise / pA/√Hz 23 22 o 31 10 o 30
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