Publications

Refine Results

(Filters Applied) Clear All

High-quality 150 nm InP-to-silicon epitaxial transfer for silicon photonic integrated circuits

Published in:
Electrochem. Solid-State Lett., Vol. 12, No. 4, January 2009, pp. H101-H104.

Summary

We demonstrate the transfer of the largest (150 mm in diameter) available InP-based epitaxial structure to the silicon-on-insulator substrate through a direct wafer-bonding process. Over 95% bonding yield and a void-free bonding interface was obtained. A multiple quantum-well diode laser structure is well-preserved after bonding, as indicated by the high-resolution X-ray diffraction measurement and photoluminescence (PL) map. A bowing of 64.12 um is measured, resulting in a low bonding-induced strain of 17 MPa. PL measurement shows a standard deviation of 1.09% across the entire bonded area with less than 1.1 nm wavelength shift from the as-grown wafer.
READ LESS

Summary

We demonstrate the transfer of the largest (150 mm in diameter) available InP-based epitaxial structure to the silicon-on-insulator substrate through a direct wafer-bonding process. Over 95% bonding yield and a void-free bonding interface was obtained. A multiple quantum-well diode laser structure is well-preserved after bonding, as indicated by the high-resolution...

READ MORE

Organometallic vapor phase epitaxy of relaxed InPAs/InP as multiplication layers for avalanche photodiodes

Published in:
J. Cryst. Growth, Vol. 310, No. 7-9, April 2008, pp. 1583-1589 (Proc. 13th Int. Conf. on Crystal Growth, in conjunction with Int. Conf. on Vapor Growth and Epitaxy and US Biennial Workshop on Organometallic Vapor Phase Epitaxy, 12-17 August 2007).
Topic:

Summary

InP1-yAsy epitaxial layers grown lattice-mismatched (LMM) on InP substrates were investigated as a new materials system for multiplication layers in Geiger-mode avalanche photodiodes (GM APDs) for detection of photons in the range 1.6-2.5 mm. LMM InP1-yAsy epilayers were grown on semi-insulating (1 0 0) InP substrates misoriented 0.2 and 2 [1 1 0] by organometallic vapor phase epitaxy at a growth temperature of 580 1C. The growth scheme used for the InP1-yAsy buffer layer was optimized based on surface step structure and X-ray diffraction. It was found that step-flow growth is a minimum criterion for obtaining good material quality. A narrower XRD full-width at half-maximum values were measured for 21-miscut substrates compared to 0.21-miscut substrates. A highquality buffer was obtained by step-grading the InP1-yAsy composition in increments of y = 0.05 over a layer thickness of 0.5 mm to a final y = 0.25. The device performance of LMM GM APDs was compared to that of measured more traditional lattice-matched GaSbbased devices. At 77 K, dark count rates of LMM devices are ~50 kHz at 5V overbias, and are comparable to GaSb-based p-i-n diodes operated in Geiger mode, while reset times of 0.02 ms are approximately 3 orders of magnitude lower than GaSb-based GM APDs.
READ LESS

Summary

InP1-yAsy epitaxial layers grown lattice-mismatched (LMM) on InP substrates were investigated as a new materials system for multiplication layers in Geiger-mode avalanche photodiodes (GM APDs) for detection of photons in the range 1.6-2.5 mm. LMM InP1-yAsy epilayers were grown on semi-insulating (1 0 0) InP substrates misoriented 0.2 and 2...

READ MORE

Polymer matrix effects on acid generation

Published in:
SPIE Vol. 6923, Advances in Resist Materials and Processing Technology XXV, 24-29 February 2008, 692319.

Summary

We have measured the acid generation efficiency with EUV exposure of a PAG in different polymer matrixes representing the main classes of resist polymers as well as some previously described fluoropolymers for lithographic applications. The polymer matrix was found to have a significant effect on the acid generation efficiency of the PAG studied. A linear relationship exists between the absorbance of the resist and the acid generation efficiency. A second inverse relationship exists between Dill C and aromatic content of the resist polymer. It was shown that polymer sensitization is important for acid generation with EUV exposure and the Dill C parameter can be increased by up to five times with highly absorbing non-aromatic polymers, such as non-aromatic fluoropolymers, over an ESCAP polymer. The increase in the Dill C value will lead to an up to five fold increase in resist sensitivity. It is our expectation that these insights into the nature of polymer matrix effects on acid generation could lead to increased sensitivity for EUV resists.
READ LESS

Summary

We have measured the acid generation efficiency with EUV exposure of a PAG in different polymer matrixes representing the main classes of resist polymers as well as some previously described fluoropolymers for lithographic applications. The polymer matrix was found to have a significant effect on the acid generation efficiency of...

READ MORE

Cryogenic YB3+-doped solid-state lasers

Published in:
IEEE J. Sel. Topics in Quantum Electron., Vol. 13, No. 3, May/June 2007, pp. 448-459.

Summary

Cryogenically cooled solid-state lasers promise a revolution in power scalability while maintaining a good beam quality because of significant improvements in efficiency and thermo-optic properties. This is particularly true forYb3+ lasers because of their relatively lowquantum defect and relatively broadband absorption even at cryogenic temperatures. Thermo-optic properties of host materials, including thermal conductivity, thermal expansion, and refractive index at low temperature, are reviewed and data presented for YAG (ceramic and single crystal), GGG, GdVO4, and Y2O3. Spectroscopic properties of Yb:YAG and Yb:LiYF4 (YLF) including absorption cross sections, emission cross sections, and fluorescence lifetimes at cryogenic temperatures are characterized. Recent experiments have pushed the power from an end-pumped cryogenically cooled Yb:YAG laser to 455-W continuous-wave output power from 640-W incident pump power at anM2 of 1.4.
READ LESS

Summary

Cryogenically cooled solid-state lasers promise a revolution in power scalability while maintaining a good beam quality because of significant improvements in efficiency and thermo-optic properties. This is particularly true forYb3+ lasers because of their relatively lowquantum defect and relatively broadband absorption even at cryogenic temperatures. Thermo-optic properties of host materials...

READ MORE