MAPS with advanced on-pixel processing

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

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

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

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

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

APS: -particle detection Source Strontium 90 -particle : 0.546 MeV

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

450 20 SNR  > 19 MIP 1.16 Noise measurements  -particle response (MPV evaluated to be equivalent to 15-20 IPs)  450 mV pixel (kTC) noise  1.16mV No SEU malfunction were reported

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

Radiation Damage

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

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

α-particle detection “analog” readout mode single α hit causes cluster response > 30 pixels involved 300-400mV “digital” (on/off) readout mode cluster size limited to 4-9 pixels 1.6V

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

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

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

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

offset from photodiode center Innovative architectures: SHARPS 10.3 mm MIP simulated response fill-factor15.08% power dissipation 823 nW / pixel Capable of both synchronous and x-y event-triggered readout Resolution: 2.6 m

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

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

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

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

MAPS with advanced on-pixel processing