WP4 Organic crystal deposition Mojca Jazbinsek Rainbow Photonics AG SOFI meeting Karlsruhe

SOFI meeting Rainbow Photonics AG Summary RB activities Jan-April 2013  Melt deposition of BNA on SOFI2 chips with CMOS electrodes:  6 samples sent to KIT on April 15, 2013 for evaluation  Melt deposition of OH1 on SOFI2 chips with electrodes  First tests

SOFI meeting Rainbow Photonics AG Melt deposition technique used  Chips are covered with a glass substrate  Material molten at the edge and flows between by a capillary force  Slow cooling -> Crystallization  Deposition process needs to be optimized for a particular chip type (surface properties)  Removal of the cover glass

SOFI meeting Rainbow Photonics AG SOFI2-CMOS metalized chips Different geometry and conditions for melt flow & crystal growth compared to chips previously tested

SOFI meeting Rainbow Photonics AG Deposition of BNA on SOFI2-CMOS chips Most of the chip: very flat surface, weak wettability of the melt  Cover (flat) glass forms a close contact with the surface  Melt flow is very slow (compared to the same chips)  Trenches with waveguides present a barrier for the flow, but once it is crossed, the melt can flow faster within the trenches (not always…)

SOFI meeting Rainbow Photonics AG Deposition of BNA on SOFI2-CMOS chips Using vacuum and melt deposition at higher temperatures, a good covering of the chip with melt has been achieved. Reproducible conditions for the crystal growth could not be achieved yet  each chip was processed individually

SOFI meeting Rainbow Photonics AG Example 1: Only a part crystalline, the rest amorphous (which later at room temperature slowly grows further, but dendritic) Previous chips: no amorphous BNA/dendrites

SOFI meeting Rainbow Photonics AG Example 2: Very thin BNA film; thickness  0 on top, but there is still material and crystallization in channels

SOFI meeting Rainbow Photonics AG Example 3: In most cases the BNA crystal stayed on chip after removing the cover. In this example, it remained mostly on the cover, but the channels still contain crystalline material Previous chips: easier cover removal

SOFI meeting Rainbow Photonics AG Example 4: Bad crystal on top (polycrystalline, holes), but seems single crystalline within the channels

SOFI meeting Rainbow Photonics AG Example 5: Low damage after removal, good single crystallinity

SOFI meeting Rainbow Photonics AG Melt deposition of OH1 Material Point group n (|| polar axis) r (highest tensor component) Melting T m (°C) Stable at T m DAST DSTMS m pm/V (χ (2) =580 µm) 256N OH1mm pm/V212Y OH2mn.m.n.m. (>60 pm/V expected)242Y DAT pm/V235Y BNAmm21.8 n.m. 30 pm/V (Dalton 2011) our estimation: ~15 pm/V 102Y DAN pm/V nm)166Y  Compared to BNA: + higher EO coefficient + higher melting temperature – higher refractive index (lower contrast, PVA cover less effective) – growth much more challenging

SOFI meeting Rainbow Photonics AG Melt deposition of OH1  Growth challenges (Dec. 2012):  Parts may stay amorphous – crystal growth easily inhibited  Dendritic growth  Slow growth: good single crystals, but many parts amorphous  Fast growth: instabilities lead to dendritic growth  The conditions change on different substrates  Growth results less reproducible as with BNA  2013: With SOFI2-CMOS chips very similar observed also for BNA

SOFI meeting Rainbow Photonics AG OH1 on bare SOFI1 (Q4 2011)  Best example

SOFI meeting Rainbow Photonics AG First tests with OH1  Deposition is challenging, no general conclusions yet

SOFI meeting Rainbow Photonics AG Conclusions  New geometry for the crystal growth brings new challenges  Once the growth is successful, this geometry is expected to be beneficial also for crystals

SOFI meeting Rainbow Photonics AG Planned / needed  Feedback from KIT (SOFI2-CMOS-BNA)  Deposition experiments with OH1  SOFI 3 (June?)  Samples: 4 SOFI2 chips left (edge of the wafer)

SOFI meeting Rainbow Photonics AG WP4 Deliverables, Milestones M4.1 [M21] Optimized processes for EO polymers and crystals with sufficient yield (RB, GO) M4.2 [M21] Processes for chalcogenides (CUDOS). M4.3 [M21] Identification of optimal electro-optic materials with respect to optical and electro-optical properties and to thermal stability (RB). M4.4 [M30] Identification of optimal electro-optic materials with respect to integration into silicon (RB). D4.1 [M24] Silicon-organic chips with EO waveguides (first device run) handed over to WP5 (RB, GO, UKA). D4.2 [M30] Report on full potential and limitations of the electro-optic materials for hybrid integration with silicon for all approaches & comparison of different solutions (GO, RB, CUDOS). D4.3 [M30] Silicon-organic QAM modulator chips (second device run) handed over to WP5 (RB, GO, UKA) D4.4 [M36] Report on electro-optic polymers and organic single crystals suitable for reproducible optical functionalization of SOI in large quantities (GO, RB). D4.5 [M40 = April] Third device run, coated and poled, handed over to WP5 (RB, GO,KIT). D4.6 [M40 = April] Chips functionalized with chalcogenides handed over to WP5 (CUDOS, KIT)