research activities on silicon radiation detectors at...

May 20, 20021st SIRAD Meeting/WorkshopG.-F. Dalla Betta

Research Activities on

Silicon Radiation Detectors at IRST

M. Boscardin, G.-F. Dalla Betta, P. Gregori, N. Zorzi

Centro per la Ricerca Scientifica e Tecnologica (ITC-irst),

Divisione Microsistemi

Via Sommarive 18, 38050 Povo (Trento)

http://www.itc.it


Microfabrication Facility 250sq.m class 10, 250sq.m class 100; 4 inch wafers

Equipment: Ion implanter;

11 furnaces ;

Mask Aligner;

Sputter metal deposition;

Dry etching: Al, SiO2, poly and Si3N4;

Dicing Saw and ball bonder.

Clean Room Staff: 4 researchers, 12 operators

Simulation and design tools: Tanner tools, SILVACO and ISE-TCAD

Testing Lab. : Manual probe station (Karl Suess PM8);

Automatic probe station (Electroglas 2001 CX) for double-sided detectors;

Parametric test system (HP4062UX, HP4145B, HP4280A, HP4192A, Keithley 2410)

Microelectronics at IRST


• Starting from 1994, ITC-IRST has been involved in the

development of silicon radiation detector technologies within an

R&D project supported by INFN.

• Currently, production and research activities on detectors are

carried on in parallel:

- Several hundreds of double-sided microstrip detectors are

being fabricated for the AMS2 and CERN/ALICE experiments

- Single-sided microstrip detectors with integrated, JFET-based

electronics and pixel detectors for X-ray imaging applications in

the medical field are being developed, in cooperation with INFN

Silicon Radiation Detectors (SRD) Project


Development of µstrip detector technologies

Double sided detectors with integratedpoly-Si bias resistors and coupling capacitors

n S i-su b s tra te-

p+

p+

p+

p+

n+

n+

S iO

T E O S 1

T E O S 2

p o ly -S i

m e ta l

o v e rg la ss

2

Layout of CMS-like detectors

Cross section of a double-sided detector


Telescope detector

Test structures

Telescope detector

a b

ALICE oriented µstrip detectors

ALICE detectora: width = 50 µmb: width = 30 µm

Double-sided, Area = 75x42 mm2 , AC-coupled, punch-through bias


Experimental results

Strip leakage current distribution Detector AC scan


ATLAS Pixel Detector prototypes

LAD

SMD

NOD

“moderated p-spray isolation”

pixel “n-on-n”

oxygen enriched substrate

n-

A specially tailored technology has been developed for the fabrication of ATLAS pixel detector prototypes on thin silicon wafers (250 µm).


N-JFET (W/L=200/12 µm)

PIN diode(0.32 mm2) Am241 spectrum acquired at room temperature

(ENC = 60 electrons rms @ τs=10 µs)

Development of detectors with integrated electronics (1)

PIN+JFET test structures


PRIN Project with Univ. of Pisa, Pavia, Trieste, Bergamo.

Microstrip detector with JFET-based source-follower

Charge sensitive preamplifier

Development of detectors with integrated electronics (2)


��

��(��

��(��

��(��

��(��

��

'HSWK >XP@

&RQFHQWUDWLRQ>DW�FP

�@

V��

V��

V��

Optimization of oxygenation processes

Oxygen concentration profiles measured by SIMS (ITME, Poland) on IRST Si samples

Irradiation tests in progress with :

• Neutrons and protons at Legnaro (collaboration with INFN Padova)

• High energy electrons at Trieste (collaboration with INFN Trieste)


Studies of radiation damage from high energy electrons (Elettra, Trieste)

• Motivated by results from

BaBar microstrip detectors

• Test structures irradiated with

900 MeV electrons

• Both surface and bulk

radiation damage observed

• Substrate type-inversion

Increasing fluence


60Co γ irradiation of integrated JFETs

Noise spectral density of single JFET (triode, W/L=100/4), before and after irradiation with 60Co up to 750kRad

Equivalent Noise Charge of the monolithic preamplifier before and after exposure to γ-ray doses of 20kGy and 40 kGy


Neutron irradiation of multiguard termination structures (ENEA Frascati)

Φ=1x1012 cm-2

(1MeV eq.)

Standard multiguard termination All-p-type multiguard termination

Φ=1x1012 cm-2

(1MeV eq.)


• Silicon radiation detectors represent one of the main research

activities at ITC-IRST

• In the near future, the need for radiation damage tests is

foreseen for:

- ALICE microstrip detectors (low fluence)

- Microstrip detectors with integrated electronics

- Oxygenated silicon wafers

- All-p-type termination structures

- New detector structures (thin and 3D, CERN RDXX)

Conclusions

research activities on silicon radiation detectors at...

Documents