Single-crystal – oriented-crystal – and epitaxy growth processes; – Forming from vapor or gaseous state – With decomposition of a precursor
Patent
1994-04-11
1995-02-14
Breneman, R. Bruce
Single-crystal, oriented-crystal, and epitaxy growth processes;
Forming from vapor or gaseous state
With decomposition of a precursor
117 90, 117 95, 117105, 117923, 437129, H01L 2120
Patent
active
053885481
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to the fabrication of optoelectronic components and in particular photonic integrated circuits.
BACKGROUND OF THE INVENTION
Photonic integrated circuits (PIC) are semiconductor chips that include several optoelectronic components (e.g. semiconductor lasers, detectors, waveguides, FET devices, etc.). Such chips can be fabricated using various techniques that have been developed for the individual components. However, because each different component (e.g. a laser and a waveguide) requires a different layer structure, that is a stack of several layers having different thicknesses and compositions, the fabrication of PIC's using these known different techniques requires many processing and growth steps.
More advanced techniques have been disclosed in the literature that make it possible to grow the layers for the different components over the surface of a substrate in a single run. This can be done by controlling the lateral variations in the growth rate over the surface of the substrate, thereby to change the bandgap of the quantum wells in a controllable way laterally over the surface of the substrate. These advanced techniques include selective growth, shadow masked growth and non-planar growth using Metal Organic Chemical Vapour Deposition (MOCVD) growth in a reactor.
For growing high quality layers, the right growth conditions are chosen so as to obtain the best layers. The growth parameters include the temperature, pressure, gas flow.
Using the known techniques provides chips including several devices that consist each of a stack of several layers having different thicknesses and compositions. The composition within a few atomic layers can be changed by changing the gas that is switched to the MOCVD reactor.
As noted above, the growth rate can be controlled for each device over the surface of the substrate and this results in a complete integrated chip including devices in which the active layers are not lying at the same height. Such a structure has some disadvantages in that the coupling between different devices (e.g. a laser and a semiconductor waveguide) is not perfect and the overall surface is not planar.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved growth technique that results in a chip structure wherein the active layers are all lying at the same height while being grown in a single growth run.
This object is achieved according to this invention by a growth method using a MOCVD growth in a reactor in which the pressure is maintained at a different value for growing each individual layer. In particular, a method is provided for fabricating a plurality of optoelectronic components including several layers grown on a semiconductor substrate in a reactor. Every layer is being grown under a predetermined individual pressure whereby the active layers of all the components are lying substantially at the same height.
This invention makes it possible for instance to grow simultaneously a plurality of first layers having an equal thickness over the entire area of a substrate using a low pressure, then second epitaxial layers having different thicknesses using an atmospheric pressure, and then again epitaxial layers having an equal thickness using a low pressure, thereby to realize a layer structure in which all active layers are lying at the same height over the area of the substrate.
The invention will be more readily understood by reference to the drawings and the description of two exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a semiconductor substrate to be processed together with a shadow mask.
FIG. 2 is a cross-sectional view across a channel in the mask shown in FIG. 1.
FIG. 3 is a diagram showing the variation in growth rate as a function of the channel width (shadow masked growth).
FIGS. 4 and 5 show the layer structures for a laser and a waveguide device grown according to the prior art and the invention respectively.
FIG. 6 schematically shows a mask for selective growth.
REFERENCES:
patent: 5212113 (1993-05-01), Azoulay et al.
G. Coudenys et al. "Lateral Bandgap Engineering for InP-Based Photonic Integrated Circuits," 4th International Conf. on Indium Phosphide and Related Materials, 21 Apr. 1992, Newport, USA, pp. 202-205.
M. Takahashi et al. "In-Plane Quantum Energy Control of InGaAs/InGaAsP MQW Structure by MOCVD Selective Area Growth," 4th International Conf. on Indium Phosphide and Related Materials, 21 Apr. 1992, Newport, USA, pp. 206-209.
E. Veuhoff et al. "Improvements in Selective Area Growth of InP Metalorganic Vapor Phase Epitaxy," 4th International Conf. on Indium Phosphide and Related Materials, 21 Apr. 1992, Newport, USA, pp. 210-3.
I. Moerman et al. "Characterization of InP/InGaAs/InGaAsP Using Atmospheric and Low Pressure MOVPE," 3rd International Conf. on Indium Phosphide and Related Materials, vol. 1, 8 Apr. 1991, Cardiff, Wales, UK p. 132.
P. Demeester et al. "Non-Planar MOVPE Growth Using a Novel Shadow-Masking Technique," J. Crystal Growth vol. 107, No. 1/4, Jan. 1991 pp. 161-165.
G. Coudenys et al. "Selective and Shadow MOVPE Growth of InP/InGaAs(P) Heterostructures and Quantum Wells," J. Crystal Growth vol. 124, No. 1/4, Nov. 1992, pp. 497-501.
P. Demeester et al. "Growth Velocity Variations During Metalorganic Vapor Phase Epitaxy Through an Epitaxial Shadow Mask," Appl. Phys. Lett. vol. 57, No. 2, 9 Jul. 1990, pp. 168-170.
T. Iwasaki et al. "Selective MOCVD Growth for Application to GaAs/AlGaAs Buried Heterostructure Lasers," Japanese J. Appl. Physics vol. 25, No. 1, Jan. 1986, pp. L66-L69.
G. Vermeire et al. "Broad Band Side-Emitting GaAs/AlGaAs/InGaAs Single Quantum Well LED's," 18th International Symposium on Gallium Arsenide and Related Compounds, 9 Sep. 1991, Seattle, USA, pp. 499-504.
C. H. Joyner et al. "Extremely Large Band Gap Shifts for MQW Structures by Selective Epitaxy on SiO.sub.2 Masked Substrates," IEEE Photonics Technology Letters vol. 4, No. 9, Sep. 1992, pp. 1006-1009.
Y. L. Wang et al. "Optical and Electrical Properties of InP/InGaAs Grown Selectively on Sio.sub.2 -Masked InP," Appl. Phys Lett. 59 (4), 22 Jul. 1991, pp. 443-445.
Coudenys Geert F. M.
Demeester Piet P. A. R.
Breneman R. Bruce
Fleck Linda J.
Interuniversitair Micro-Elektronica VZW
LandOfFree
Method of fabricating optoelectronic components does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of fabricating optoelectronic components, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of fabricating optoelectronic components will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-281254