1. SPiDeR  First beam test results of the FORTIS sensor FORTIS 4T MAPS Deep PWell Testbeam results CHERWELL Summary J.J. Velthuis for the SPIDER collaboration

2. SPiDeR  FORTIS FORTIS is the first 4T MAPS aimed at Particle Physics 0.18µm CMOS 12µm epi layer Uses INMAPS technology 13 different type of pixels Tested 3 types of sensors: –Standard epi –Standard epi + deep Pwell islands –High res epi + deep Pwell islands Deep Pwell islands are first step towards in-pixel data processing STFC IP

3. SPiDeR  MAPS Charged particle generates free charge carriers in epitaxial layers. Due to doping profiles, electrons are confined to epitaxial layer. Electrons diffuse. When close to diode electrons collected

4. SPiDeR  FORTIS FORTIS is the first 4T MAPS for Particle Physics –3T CMOS Simple architecture Readout and charge collection node are the same –4T CMOS Three additional elements Readout and charge collection area are at different points

5. SPiDeR  4T Pixel Advantages Low Noise –readout node separated from charge collection area –The reset noise and pixel fixed pattern noise (FPN) can be removed by in-pixel correlated double sampling read out (CDS) High Conversion Gain –Charge is collected on large diode then transferred to the floating diffusion –Large C gives larger depleted area and complete charge collection –Small C yields large gain e- V = q/C small V = q/C large 5

6. SPiDeR  Deep Pwell Problem in MAPS: –PMOS electronics need Nwell –Nwell acts as charge collection diode –So can’t make PMOS without losing huge amount of Q New development: make deep pwell with Nwell inside  can do CMOS –Road to data processing in pixel Some FORTIS have empty deep pwell islands to test effect of Q collection

7. SPiDeR  Substrate Resistivity High resistivity (intrinsic) silicon enlarges the depletion region to fully occupy the pixel –Majority of deposited charge now falls in a depletion region and is collected by electric field –Improved charge collection efficiency –Faster charge collection (drift vs diffusion) Some FORTIS have high res

8. SPiDeR  Some test beam pictures

9. SPiDeR  We see hits… Beam at SPS 120 GeV pions Using EUDET telescope C2 on F1.1 high res

10. SPiDeR  EUDET telescope Telescope 6 planes, 18.4µm pitch, binary readout –single hit resolution: 18/√12=5.3µm FORTIS at 572 mm Simulated telescope error 3.2±0.2µm –Consistent EUDET values, only is different error in X and Y (see talk Ingrid Gregor) simulation

11. SPiDeR  C-structures 4 test pixels: –128 × 128 pixels –15µm pitch –C structures have different W and L for source follower Three different wafers –standard epi –standard epi plus Deep PWell islands –high resistivity epi plus Deep PWell islands plus implant to prevent FD and diode from merging Read out speed 15 frames per second STFC IP

12. SPiDeR  C-structures: Noise Noise is spread around pedestal after hit removal All 4 pixel types have same noise. Difference in noise between various wafers minimal –21.9 ADC high resistivity plus Deep PWell islands –20.3 ADC Standard epi –18.7 ADC Standard epi + deep PWell islands DPW HresStd

13. SPiDeR  C-structures: Signal Cluster search: seed 5×noise, neighbours 2×noise, max cluster size 5×5 pixels Low signal peaks due to incomplete clusters. Signals in standard epi + deep Pwell islands highest Signals in high res epi layer lowest. –Naively expected to be higher: high res should increase depleted area and thus charge collection efficiency DPW HresStd

14. SPiDeR  C-structures: Cluster size Cluster size for high res much larger. –Charge travels much further –Charge per pixel much lower Deep PWell islands no effect cluster size DPW HresStd

15. SPiDeR  C-structure: summary table First time a 4T structure was successfully used for the detection of MIPs S/N ratios very high –S/N>100

16. SPiDeR  C-structures: position resolution Positions reconstructed using: –CoG, –2 pixel clusters –eta Resolution worse for High res: due to large charge spread. Number still contains 3.2µm telescope uncertainty DPWHres Std

17. SPiDeR  C-structure: summary table (II) Resolutions corrected for telescope uncertainty. Large errors due to uncertainty in telescope error. Algorithms do not make much difference in resolution indicating that the charge division is reasonably linear.

18. SPiDeR  The future: Cherwell Uses Deep Pwell and 4T to achieve 100% fill factor with integrated sensor and readout electronics Incorporation of complex logic within a pixel Investigation of data reduction/clustering –CDS in-pixel and in-pixel amplification –Low power using rolling shutter readout First attempt housing ADC in the islands has been received.

19. SPiDeR  Summary FORTIS is first 4T MAPS for Particle Physics Using the Deep Pwell technology, we can incorporate full CMOS circuits in pixel. Tested three different wafers: –Standard epi –Standard epi with Deep Pwell islands –High resistivity epi with Deep Pwell islands Deep Pwell islands have no detrimental effect on the signal. FORTIS works really well: –S/N>100 observed for 15µm pitch pixels –Position resolution <2µm Cherwell: first device with ADC in deep Pwell islands has been received. We thank the EUDET collaboration for the provided infrastructure and travel funds