Evaluation of SiGe Technology - Status Report - US-ATLAS Upgrade Meeting 3-May-2007 Alex Grillo

1. Evaluation of SiGe Technology- Status Report - US-ATLAS Upgrade Meeting 3-May-2007 Alex Grillo SCIPP - UCSC Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

2. The SiGe Bipolar Option 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. Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

3. Participating Institutions (US) • 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 Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

4. Participating Institutions (non-US) • 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 Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

5. Radiation Testing • 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 Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

6. Focus on Two IBM Technologies • 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. Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

7. Preliminary Results for the IBM 8HP 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 Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

8. Design of Front-End SiGe Test Chip 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. Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

9. Test Setup With no “back-end” on the test chip a special test setup was needed. PC 8-bit command SiGe Chip Board Spartan3 Board Plug-in Board NI6534 8 LVDS channels 16-bit data (16th bit = valid data) Trigger Cal. strobe Amplitude Pulser Voltages Power, Vthres 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. Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

10. Measured vs. Simulation Results 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 front-end 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. Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

11. Test Chip on IBM 8HP • 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. Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

12. Plans • 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 Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting

13. UCSC Budget for FY08 • IC Fab $85k • Assumes 8WL; 8HP will cost considerably more • Georgia Tech 30k • Travel 4k • Misc. M&S 5k • Labor 94k • Includes: 17% FTE EE 25% FTE Tech Physicist 108% FTE ETech 25% FTE Undergrad Student • Indirects 49k • Total $267k Evaluation of SiGe Technology – Status ReportUS-ATLAS Upgrade Meeting