Deposition of AlOx/SiN stack and SiN for high efficient bifacial PERC solar cells using only one deposition system MAiA 3in1

Transcription

1 SNEC PV Power Expo and Conference 2017 Deposition of AlOx/SiN stack and SiN for high efficient bifacial PERC solar cells using only one deposition system MAiA 3in1 E. Vetter 1, T. Grosse 1, H.P. Sperlich 1, G. Köhler 1, M. Meyer 1 1 Meyer Burger (Germany) AG

2 1. Motivation Al BSF Solar Cell SiNA Front side SiN deposition PERC Solar Cell MAiA Rear side AIOx + rear SiN deposition SiNA Front side SiN deposition 2

3 1. Motivation Why not all in one? PERC Solar Cell MAiA 3in1 Front side SiN + Rear side AIOx + SiN deposition Meyer Burger Germany Pilot system PM1: plasma source 1 and 2 for AlOx deposition top down PM1: plasma source 3 and 4 for surface plasma oxidation on front side PM2: 6 linear MW plasma source top down for SiN capping layer PM3: 6 linear MW plasma source bottom up for ARC No additional transfer chamber between SiN chamber 1 and 2 3

4 Cell Efficiency (%) Meyer Burger & SERIS PERx Roadmap Bifacial p-perc (T) AlOx/SiN Passivation for bifacial PERC and PERT bifacial PERC/T with busbar or smart wire connecting technology 3. N-type PERC/T AlOx/SiN passivation of Boronemitter 4. Passivated Contacts PERC optimization MAiA 3in1 MAiA R3 Tunnel oxide with SQi Doped poly-si with adapted MAiA system Metal oxides with adapted MAiA system Meyer Burger and SERIS Al-BSF PERC n-perx 19.5 n-perx (passivated contacts) 19 Year Qualification of whole process and material flow for p-type PERC and n- type PERL/T technology at technology center HOT 4

5 20,263 78, , ,4733 Meyer Burger / ,563 39, ,217 39, Front Side Improvements Gradient layer with MAiA 3in1 Back Side Sunny Side Gradient layer with improved surface passivation Microwave power optimization for interface layer ,5 Voc (in mv) Jsc (in ma/cm²) 40,0 39,8 39,6 39,4 39,2 FF (in %) Efficiency (in %) 20,8 79,0 20,6 78,5 20,4 78,0 20,2 77,5 1_Reference 2_Improved ARC 20,0 1_Reference 2_Improved ARC 8

6 79, , , ,6488 Meyer Burger / ,833 39, ,362 39, Front Side Improvements N 2 O pre - oxidation Back Side Sunny Side Oxidation of front surface within AlOx deposition chamber Thin inline plasma SiO improves front side passivation No additional process step necessary inline in MAiA 3in1 possible ,0 79,5 79,0 Voc (in mv) 39,8 39,6 39,4 39,2 FF (in %) 39,0 21,0 Efficiency (in %) 20,7 20,4 Jsc (in ma/cm²) 78,5 20,1 78,0 3in1 + Inline Oxidation 3in2 19,8 3in1 + Inline Oxidation 3in2 9

7 3. Bifacial PERC Solar Cells Experimental Results Texturing Diffusion Edge isolation Passivati on/arc Laser Ablation Screen Printing Firing/ Test 100nm AlOx + SiN Stack 130nm 0.2g Busbarless screen printing for Smart Wire Connection module Technology (SWCT) 0.3g 0.5g 0.8g 12

8 5,3201 5,2318 Isc (front and back measurement) 5,8343 5,7927 6,8045 6,6268 6,4975 6,6087 9,5612 9,5524 9,5563 9,5747 9,5844 9,5842 9,6252 9, Bifacial PERC Solar Cells Experimental Results Isc front Isc back Improvement of Isc back side for bifacial application up to 30% with optimized rear etching and stack deposition Comparable Isc front side 6 5 AlOx + SiN Rear etching 100nm 130nm 0.2g 100nm 130nm 0.3g 100nm 130nm 0.5g 100nm 130nm 0.8g Even better Isc back side expected for further AlOx/SiN stack optimization 13

9 55, ,37 Bifaciality (%) 60, , , , , , Bifacial PERC Solar Cells Experimental Results High bifaciality due to busbarless screen printing SWCT technology 15% better bifaciality by optimization of rear etching and stack deposition AlOx + SiN Rear etching 100nm 130nm 0.2g 100nm 130nm 0.3g 100nm 130nm 0.5g 100nm 130nm 0.8g 1. Bifaciality determination at STC: φ Isc = Isc rear Isc front ; 14

10 3. Bifacial PERC Solar Cells Experimental Results Thin AlOx Can we do AlOx very thin with reasonable uniformity and low TMAl consumtion??? Yes, we can!!! 10

11 5mm LL 50mm LL 50mm LL 5mm LL 5mm L 50mm L 50mm L 5mm L 5mm CL 50mm CL 50mm CL 5mm CL 5mm CR 50mm CR 50mm CR 5mm CR 5mm R 50mm R 50mm R 5mm R 5mm RR 50mm RR 50mm RR 5mm RR Meyer Burger / Bifacial PERC Solar Cells Experimental Results 400 C AlOx on CEM Vaporizer with LFM (direct injection with liquid flow control) TMAl = 200 mgm = 12 g/h This run done at target speed & measured with fixed RI 1.60!!! nm AlOx UNIFORMITY across 4x6 tray AlOx thickness (@ 200cm/min) Mean: 8.3 nm Uni. wiw % Uni. wtw = 3.6 % 0 Position Refractive Index Mean: 1.60 (fix) we got 8.3nm *0.7 = 6.0 nm on tex. Front 11

12 J 0e (fa/cm 2 ) 4. n-type PERT Passivation Passivation of p + emitter 10 3 planar textured p + silicon 10 2 Thermal oxide [Kerr et. al.] 10 1 ALD Al 2 O 3 [Hoex et. al.] PECVD AlO x /SiN x [Duttagupta et. al.] industrially fired sheet resistance ( /sq) Same passivation quality of inline PECVD (AlOx/SiN) compared to ALD 17

13 4. n-type PERT Passivation Surface Passivation J 0e/side < 25 fa/cm 2 iv OC ~ 700 mv 18

14 Summary/Conclusion MAiA 3 in 1 : MAiA 2.1 PECVD equipment with the ability to process the whole PERC deposition processes in one tool. With this arrangement further cost benefits are given. MAiA 3 in1 and passivation : Through using of pre oxidation processes and new deposition processes further improvement of passivation and increase of PERC cell efficency have been seen. MAiA 3 in 1 and bifaciality as well as thin AlOx layer: Bifacial PERC cells are processed on the MAiA tool. Improvements from the rear side has been seen. Thin AlOx/SiN stack layer can be esablished through thin AlOx by maintaining the passivtion quality MAiA 3 in 1 and n-pert : Passivation quality of the p+ emitter is comparable to the ALD deposition processes and the surface passivation uniformity of the PERT cells were excellent. 14

15 5. Summary/Conclusion 15

16 MAiA 3in1 Front side SiN + Rear side AIOx + SiN deposition Thank you for your attention. Funded in AdmMo ( ) Meyer Burger Germany An der Baumschule Hohenstein-Ernstthal Germany Phone: +49 (0) Mobile: +49 (0) thomas.grosse@meyerburger.com

17 Cost p. wafer [ ] Meyer Burger / Cost p. wafer [ ] 1. Motivation Why not all in one? Advantages Less production equipment means: Less invest for same output Less automation, floor space and facility connection Less man power required Less mechanical yield loss = Lower Cost of ownership! , Cost of ownership Front SiN + Rear AlOx+SiN 100% SiNA + MAiA CAPEX / throughput Front SiN + Rear AlOx+SiN 100% 79% MAiA 3in1 100% 80% 60% 40% 20% 0% 100% 80% MAiA 3in1 21% lower CoO 26% lower Capex SiNA + MAiA 74% MAiA 3in1 60% 40% 20% 0% 17

18 Annex PID measurement N2O pretreatment 18

19 286, ,99 289, , , ,916 Calculated Module Power 292, , , , , , , , , , Bifacial PERC Solar Cells Module Calculation SWCT Technology Bifacial SWCT module* Monofacial SWCT module Results: Increased module power with decreased rear side polish and AlOx/SiN stack deposition Up to 10% higher module power with bifacial PERC modules possible 90% less aluminum paste consumption 280 AlOx + SiN Rear etching 100nm 130nm 0.2g 100nm 130nm 0.3g 100nm 130nm 0.5g 100nm 130nm 0.8g *Albedo = 20% 2. Specific P total calculation: P total =P front +P front φ Isc Albedo ground material albedo snow 0,45-0,9 desert 0,3 greenfield 0,18-0,23 asphalt 0,15 15

20 4. n-type PERT Passivation Comparison MAiA PECVD vs. ALD After firing, the ivoc is similar to our baseline value. O2 test and UV-transparent SiNx RI 1.9 test split shows similar results. Baseline ivoc~687mv All samples are fired at LGE

21 4. n-type PERT Passivation Overview Source: S. Duttagupta, PhD thesis, SERIS-NUS (2014) Best in class passivation quality of different dielectric layer using MAiA system 19

22 Overview 1. Motivation 2. MAiA 3in1 optimization Gradient layer with MAiA 3in1 N2O Oxidation 3. Bifacial PERC Solar Cells Optimization of back side stack Experimental Results 4. N-type PERT passivation 5. Summary/Conclusion 22

23 Overview 1. Motivation 2. MAiA 3in1 optimization Gradient layer with MAiA 3in1 N2O Oxidation 3. Bifacial PERC Solar Cells Optimization of back side stack Experimental Results 4. N-type PERT passivation 5. Summary/Conclusion 23

24 Overview 1. Motivation 2. MAiA 3in1 optimization Gradient layer with MAiA 3in1 N2O Oxidation 3. Bifacial PERC Solar Cells Optimization of back side stack Experimental Results 4. N-type PERT passivation 5. Summary/Conclusion 24

25 Overview 1. Motivation 2. MAiA 3in1 optimization Gradient layer with MAiA 3in1 N2O Oxidation 3. Bifacial PERC Solar Cells Optimization of back side stack Experimental Results 4. N-type PERT passivation 5. Summary/Conclusion 25

26 Overview 1. Motivation 2. MAiA 3in1 optimization Gradient layer with MAiA 3in1 N2O Oxidation 3. Bifacial PERC Solar Cells Optimization of back side stack Experimental Results 4. N-type PERT passivation 5. Summary/Conclusion 26

27 2. Front Side Improvements N 2 O pre - oxidation No negative impact from wrap around in MAiA 3in1 deposition visible in EL EL marks from printing interruptions Droplets probably not sufficient dried and handling marks from manual handling Transport marks from wet chemistry 10

28 4. n-type PERT Passivation Surface Passivation MAiA PERC AlOx for n-pert Front Can we achieve ALD-like results at Target throughput wph??? Yes, we can!!! MAiA demonstrate ALD like performance at n-pert customer Joint development work for MAiA 3.0 (4000+ wph) ongoing!!! 28

29 4. n-type PERT Passivation Comparison MAiA PECVD vs. ALD After post annealing of PECVD AlOx, the ivoc is similar to our ALD case. Post anneal 조건 : 526, 5min