WP4 Organic crystal deposition

Mojca Jazbinsek

Rainbow Photonics AG

SOFI meeting Karlsruhe 2013-04-22

SOFI meeting 2013-04-22 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 2013-04-22 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 2013-04-22 Rainbow Photonics AG

SOFI2-CMOS metalized chips

Different geometry and conditions for

melt flow & crystal growth compared to

chips previously tested

SOFI meeting 2013-04-22 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 conditions

@previous 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 2013-04-22 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 2013-04-22 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 2013-04-22 Rainbow Photonics AG

Example 2:

Very thin BNA film; thickness 0 on top, but there

is still material and crystallization in channels

SOFI meeting 2013-04-22 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 2013-04-22 Rainbow Photonics AG

Example 4:

Bad crystal on top (polycrystalline, holes), but

seems single crystalline within the channels

SOFI meeting 2013-04-22 Rainbow Photonics AG

Example 5:

Low damage after removal, good single

crystallinity

SOFI meeting 2013-04-22 Rainbow Photonics AG

Melt deposition of OH1

Material Pointgroup

n (|| polar axis)

r(highest tensorcomponent)

Melting Tm (°C)

Stableat Tm

DASTDSTMS m 2.1 50 pm/V

(χ(2)=580 pm/V @1.5 µm) 256 N

OH1 mm2 2.1 50 pm/V 212 Y

OH2 m n.m. n.m. (>60 pm/V expected) 242 Y

DAT2 2 1.5 8 pm/V 235 Y

BNA mm2 1.8n.m. 30 pm/V (Dalton 2011)our estimation: ~15 pm/V

102 Y

DAN 2 1.6 13 pm/V (@633 nm) 166 Y

Compared to BNA: + higher EO coefficient+ higher melting temperature– higher refractive index (lower contrast, PVA cover less effective)– growth much more challenging

SOFI meeting 2013-04-22 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 2013-04-22 Rainbow Photonics AG

OH1 on bare SOFI1 (Q4 2011)

Best example

SOFI meeting 2013-04-22 Rainbow Photonics AG

First tests with OH1

Deposition is challenging, no general

conclusions yet

SOFI meeting 2013-04-22 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 2013-04-22 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 2013-04-22 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)