1. MAPS with advanced on-pixel processing
D. Biagetti (1, 2), G.M. Bilei(1) , P. Ciampolini(1,3),
P. Delfanti(1, 3), A. Marras(1,3), G. Matrella(1, 3), D. Passeri(1, 2),
P. Placidi(1, 2), M. Petasecca(1, 2), L. Servoli(1)
(1) Istituto Nazionale di Fisica Nucleare
Sezione di Perugia – Italy
(2) Dipartimento di Ingegneria Elettronica e dell’Informazione
Università degli Studi di Perugia - Italy
(3) Dipartimento di Ingegneria dell’Informazione
Università di Parma - Italy

2. Outline APS: innovative architectures  ray  particle  particle WIPS
SHARPS
in-pixel CDS

3. RAPS 01 – 02 RAPS01 prototype UMC 0.18 mm technology RAPS02 prototype
Digitally configurable photodiode bias point and decision threshold level
RAPS02 prototype
4-14m
10.3m
APS architecture
WIPS architecture
SHARPS architecture

4. APS: -ray detection
Source
Americium 241
-ray : 60 keV
12-21 keV

5. APS: -particle detection
single α hit causes cluster response > 30 pixels involved
Source
Americium 241
-particle : 5.4 MeV

6. APS: -particle detection
Source
Strontium 90
-particle : MeV

7. Test results Cluster signal distibution for 90Sr (  ) source.
Volt
Cluster signal distibution for 141Am (  ) source.
Volt
MPV evaluated to be
equivalent to about 20 MIPs

8. Noise measurements SNR  >  -particle response  450 mV 450
(MPV evaluated to be equivalent to IPs)
 450 mV
SNR  20
450
1.16
> 19
MIP
pixel (kTC) noise  1.16mV
No SEU malfunction were reported

9. Photodiode Pixel 3D physical simulation (device/circuit) ~tens of mV
~tens of nsec
VDD
RESET
FTD
OUT
Particle
3D physical simulation
(device/circuit)

10. Radiation Damage

11. Configurable amplification
Source
IR laser =875nm
photodiode
analog amplification

12. Configurable amplification
Source
IR laser =875nm
photodiode
digital amplification

13. α-particle detection “analog” readout mode
single α hit causes cluster response > 30 pixels involved mV
“digital” (on/off) readout mode
cluster size limited to 4-9 pixels
1.6V

14. Innovative architectures: goals
APS
source follower: low in-pixel amplification factor
1 output pin per pixel: limits on scalability
sequential scan: limits on readout frequency
Proposed solutions
exploit CMOS features to achieve a more efficient in-pixel amplification
x-y readout
event-triggered readout

15. Innovative architectures: WIPS
row
column
VTH
weakly inverted MOS
BASIC IDEA

16. Innovative architectures: WIPS
10.3 mm
uniform exposition to 976.2 nm, 1.41 W/mm2 laser source
pmos nwell: parassite charge collection risk
weakly inverted MOS: power dissipation (20 W / pixel)
MIP simulated response
x-y read-out approach may reduce read-out times by a
(m +n )/(m xn) factor in a (m xn) array

17. Innovative architectures: SHARPS
row
column
BASIC IDEA
self reset
high-gain amplification stage
A/D
internal A/D conversion

18. Innovative architectures: SHARPS
offset from
photodiode
center
10.3 mm
MIP simulated
response
fill-factor 15.08%
power dissipation 823 nW / pixel
Capable of both synchronous
and x-y event-triggered readout
Resolution: 2.6 m

19. Innovative architectures: SHARPS
delayed
self reset
GND
fast
VDD
A/D
A/D
event triggered mode
sequential scan mode

20. Innovative architectures: CDS in pixel
BASIC IDEA
column
output
read
CDS
reset
high
ampl.
on-pixel Correlated Double Sampling circuitry
10.3 mm

21. Innovative architectures: CDS in pixel
VREF
gnd
VSIG
VSIG -VREF
RESET
SAMPLE
signal integration period
reference
sampling
signal
CDS
reset

22. Conclusions
Active Pixel Sensor systems have been designed and fabricated in a commercial 0.18 m CMOS technology.
TCAD tools thoroughly exploited in the design phase.
Preliminary test results:
satisfactory response to , , , X, IR stimuli
promising performance (SNR).
Innovative architectures introduced.
Extensive test to be completed:
statistical characterization;
dynamic performance;
radiation damage analysis;
beam test.
Next generation chip