ATLAS
Evaluation of SiGe Technology
- Status Report US-ATLAS Upgrade Meeting
3-May-2007
Alex Grillo
SCIPP - UCSC
3-May-2007
1
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
The SiGe Bipolar Option
ATLAS
Along with the 130 nm CMOS technology, IBM offers two silicon-germanium
(SiGe) bipolar options (CMOS8HP and CMOS8WL) to allow full biCMOS ICs.
If these technologies are sufficiently radiation hard, a SiGe bipolar front-end may
significantly reduce the power dissipation of the readout IC.
The 8WL is a less expensive option and may provide sufficient performance.
There is interest for both the upgrade Inner Tracker and the LAr Calorimeter.
3-May-2007
2
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Participating Institutions (US)
ATLAS
• UCSC
– Project coordination and general data management
– Neutron and Proton irradiation studies
– Inner Tracker front-end IC design
• Georgia Tech
– Expert in SiGe technologies, source of test structures
• BNL
– Gamma irradiation studies
– IC design for LAr
• Penn
– Will test gamma irradiated parts including annealing studies
– IC design for LAr
• Columbia
– Not yet started, interested in doing proton studies
– IC design for LAr
• LBNL
– New addition – helping to analyze data and device performance
3-May-2007
3
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Participating Institutions (non-US)
ATLAS
Spain:
• CNM Barcelona
– So far irradiation studies on German IHP technologies
– Will do neutron irradiations of IBM 8WL and
low dose rate effect (LDRE) studies
France:
• IN2P3
– Working on AMS 0.35 mm technology for LAr and ILC applications
3-May-2007
4
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Radiation Testing
ATLAS
Arrays of transistors have been obtained for three generations of IBM SiGe
technologies (from Georgia Tech), the 5HP/AM, 7HP and 8HP, and for two
SiGe technologies from the company IHP.
For IBM technologies, irradiations have been done with:
• Gammas up to 100 Mrad
– Some parts died due to ESD and broken bonds
– More parts being irradiated to 100 Mrad
– 1 Mrad, 10 Mrad and 50 Mrad not yet analyzed
• Neutrons up to 6x1015 n/cm2
– Initial post-rad testing showed some odd results – contamination found
on some irradiation PCBs
– Retesting and analysis in progress
• Protons up to 3x1015 p/cm2
– Not all requested fluences reached due to CERN PS problems last year
– Still trying to understand some data, especially bias vs. non-bias results
3-May-2007
5
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Focus on Two IBM Technologies
ATLAS
When this program started, it was not clear which technologies might be
readily available for the Upgrade. Therefore, attempts were made to test
several, possibly to learn the differences in rad-hardness.
Now with the frame contract between IBM and CERN, the two IBM
technologies available through that contract are the most interesting.
• It was a fortunate coincidence that our collaborator from Georgia Tech
(J. Cressler) had been working closely with IBM, which meant we had
already started to evaluate one of these two (the 8HP).
• We only learned of the 8WL later and so it was not included in the original
test sample.
The 8WL is less expensive with lower electrical performance.
• The specifications for 8WL indicate that its electrical performance is
probably quite adequate for our needs.
• However, Cressler has not worked with the 8WL and we have no knowledge
of its radiation hardness compared to the 8HP.
We just received a few 8WL parts from Georgia Tech.
More are promised from IBM through CERN.
3-May-2007
6
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Preliminary Results for the IBM 8HP
ATLAS
Gamma Irradiation
Neutron Irradiation
Proton Irradiation
Arrows show
typical bias
for large
front
transistor
These results look quite promising given the Inner Tracker radiation specification of:
Short Strips: 1x1015 nEq/cm2 displacement and 24 Mrad ionization
Long Strips: 5x1014 nEq/cm2 displacement and 5 Mrad ionization
3-May-2007
7
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Design of Front-End SiGe Test Chip
ATLAS
To gain some experience designing with SiGe technology, UCSC designed a
small test IC (the HRFE) using the IHP SG25H1 SiGe BiCMOS process
through Europractice. This was an inexpensive test vehicle and roughly
equivalent to IBM’s first generation SiGe technology married to 0.25 mm
CMOS.
3-May-2007
8
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Test Setup
ATLAS
With no “back-end” on the test chip a special test setup was needed.
SiGe
Chip
Board
8-bit command
8 LVDS Spartan3 Plug-in
NI6534
channels
Board
Board 16-bit data
(16th bit = valid data)
Cal.
strobe
PC
Trigger
Amplitude
Pulser
Power, Vthres
Voltages
On a command from the PC, the Spartan-3 (Xylinx) chip sends multiple triggers to
the Pulser and collects the number of hits recorded by the chip under test in a given
time interval. The PC monitors the Spartan-3 output data bus, and reads out the
number. This procedure is repeated for a set of Amplitudes and Voltages.
3-May-2007
9
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Measured vs. Simulation Results
ATLAS
Noise vs. Front-end Load was simulated and measured using two different bias
settings for the front transistor as might be used for short and long strips of the
upgraded silicon tracker.
Measured shaping time is
17ns – 19ns
Measured analogue current
is 32.8 mA plus the frontend transistor bias,
i.e. 186 mW and 346 mW
for the short and long
strips.
The measured noise agrees well with the simulations showing that acceptable
noise can be achieved at these very low power levels.
3-May-2007
10
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Test Chip on IBM 8HP
ATLAS
In late 2006 Cressler’s group at Georgia Tech made a fabrication submission
to IBM on the 8HP process. There was a small open space available so they
invited us to include a pre-amp design.
With only 1mm2 available, the design could only include the pre-amp and
shaper for 8 channels.
• The design is basically the same as the previous IHP submission
except that the comparator is removed and a voltage adjustment for
the shaping time is added.
We are expecting to have some parts back later this month.
3-May-2007
11
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
Plans
ATLAS
 Complete initial gamma total does irradiations of 8HP, 7HP and 5AM.
•
BNL & Penn
 Finish analysis of initial neutron & proton irradiations of 8HP, 7HP & 5AM.
•
UCSC & LBNL
 Complete initial total dose/fluence tests of 8WL with gammas & neutrons.
• Irradiations at BNL (with Penn) & Ljubljana (by Barcelona)
 Test 8HP test chip when it arrives.
• UCSC
 If initial 8WL radiation data looks good, choose it for first prototype IC.
 Design and submit for fabrication full front-end (Pre-amp through
comparator) IC for 64 or 128 channels.
• UCSC
 Initiate Low Dose Rate Effect (LDRE) study of 8WL and 8HP.
• Barcelona & UCSC
 Initiate final radiation study to qualify either 8WL or 8HP for the Upgrade.
• Perhaps all
3-May-2007
12
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC
UCSC Budget for FY08
ATLAS
• IC Fab
$85k
– Assumes 8WL;
8HP will cost considerably more
•
•
•
•
Georgia Tech
Travel
Misc. M&S
Labor
30k
4k
5k
94k
– Includes:
• Indirects
• Total
3-May-2007
13
17% FTE EE
25% FTE Tech Physicist
108% FTE ETech
25% FTE Undergrad Student
49k
$267k
Evaluation of SiGe Technology – Status Report
US-ATLAS Upgrade Meeting
A.A. Grillo
SCIPP-UCSC