GB2243241A - Heterojunction bipolar transistor and optical waveguide device for monolithic integration - Google Patents
Heterojunction bipolar transistor and optical waveguide device for monolithic integration Download PDFInfo
- Publication number
- GB2243241A GB2243241A GB9008880A GB9008880A GB2243241A GB 2243241 A GB2243241 A GB 2243241A GB 9008880 A GB9008880 A GB 9008880A GB 9008880 A GB9008880 A GB 9008880A GB 2243241 A GB2243241 A GB 2243241A
- Authority
- GB
- United Kingdom
- Prior art keywords
- layers
- layer
- transistor
- waveguide device
- epitaxial
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 36
- 230000010354 integration Effects 0.000 title description 5
- 238000000034 method Methods 0.000 claims abstract description 19
- 239000004065 semiconductor Substances 0.000 claims abstract description 12
- 239000000758 substrate Substances 0.000 claims abstract description 10
- 239000010410 layer Substances 0.000 claims description 85
- 238000005253 cladding Methods 0.000 claims description 9
- 238000005530 etching Methods 0.000 claims description 9
- 239000012792 core layer Substances 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 5
- 229910001218 Gallium arsenide Inorganic materials 0.000 claims description 4
- 229910000980 Aluminium gallium arsenide Inorganic materials 0.000 claims description 2
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 claims description 2
- -1 InGaAlAs Inorganic materials 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000001465 metallisation Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000005094 computer simulation Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/1443—Devices controlled by radiation with at least one potential jump or surface barrier
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Bipolar Transistors (AREA)
Abstract
A method for forming a monolithic integrated structure including a heterojunction bipolar transistor and an optical waveguide device which method comprises forming on a substrate (14) a plurality of successive epitaxial semiconductor layers, said layers being selectively etched to provide on said substrate a first structure of said transistor and a second structure of said waveguide device. <IMAGE>
Description
HETEROJIJNCTION BIPOLAR TRANSISTOR AND OPTICAL
WAVEGUIDE DEVICE FOR MONOLITHIC INTEGRATION
The invention relates to a method of forming a monolithic integrated structure including a hetrojunction bipolar transistor and an optical waveguide device.
The drive voltages required by optical switches and modulators are typically higher than standard electronic logic levels, so external drive circuits are normally required. The ability to place the drive circuit for the switch on the same chip as the switch itself permits interfacing to be achieved at standard electronic logic levels, thus avoiding the need for external buffer amplification. Furthermore the close proximity of the switch and its drive transistor is highly advantageous in high speed designs. The ability to monolithically integrate the optical waveguide devices with complex electronic circuits such as amplifiers and logic gates further extends the capability of the optoelectronic integrated circuit; for example selfrouting and self-biasing functions may be realised within a monolithic optical switch component.As in other areas of electronics, monolithic integration of the separate functions should yield improvements in cost, reliability and functionality.
Previously published work has demonstrated a transistor and a simple on/off modulator combined in a single device (Y.Okada et al "Fabrication of double graded hetrojunction bipolar transistor waveguide structure optical intensity modulator" Proc. IOOC89, Kobe,
Japan). Combining the functions in this way limits the flexibility severely: more complex electronic functions (e.g. logic circuits) cannot easily be included in such a scheme. Further more the above publication does not describe the integration of alternative optical waveguide device functions such as a four-port optical switch.
The discrete optical waveguide devices and HBT circuits described to date are based on mutually incompatible semiconductor structures. To integrate such devices monolithically would demand repeated epitaxial growth processes during device fabrication, which would complicate the processing considerably and make high yield and reliability more difficult to achieve. In the present invention the electronic and optical devices share a common epitaxial layer structure requiring only a single growth step. This major advantage has been achieved without significant compromise in the performance either of the optical device or of the HBT.
According to the invention that is provided a method of forming a monolithic integrated structure including a hetrojunction bipolar transistor and an optical waveguide device which method comprises forming on a substrate a plurality of successive epitaxial semiconductor layers, said layers being selectively etched to provide on said substrate a first structure of said transistor and a second structure of said waveguide device.
In one embodiment of the present invention the purality of layers include first, second, third, fourth and fifth epitaxial layers, said third layer providing a waveguide core layer of the waveguide device, said second and fourth layers providing lower and upper cladding layers for the core layer, the cladding layers being of a lower refractive indent than the core layer and said first and third layers providing contact layers of the waveguide device. The etching of said layers include etching a rib into the fourth and fifth layers of said waveguide device. The second, third and fourth epitaxial layers provide a collector for said transistor, said fifth epitaxial layer provides a base of said transistor and said first epitaxial layer provides a contact layer for the transistor, an emitter is provided on said base of the transistor.The fifth layer has a doping opposite to the doping of the first, second, third and fourth layer.
Preferably said plurality of layers are formed of a material selected from InP, InGaAsP, InGaAs, InGaAlAs, GaAs and AlGaAs and said substrate is a layer of InP, GaAs or Si.
The structures for integrated optical switch/modulator elements and heterojunction bipolar transistors (HBTs) are particularly suitable for monolithic integration. Integrated structures of this type will be used in optical switching and signal processing systems in order to provide standard electronic logic level interfaces to the optical devices and for on-chip electronic processing related to the optical function. The novel design presented here needs only one epitaxial growth process, with the same semiconductor layer structure being employed for both the HBT and the optical waveguide device. The relative simplicity of the device structures should lead to reduced manufacturing costs for integrated
HBT/optical waveguide devices and improved production yield, without major compromise in the performance of either the transistor or the optical device.
The invention will now be described further by way of example with reference to the accompanying drawings in which:
Figure 1 illustrates a waveguide structure for modulator or switch;
Figure 2 illustrates a structure of hetrojunction bipolar transistor (HBT); and,
Figure 3 illustrates an integrated structure for HBT and optical waveguide device embodying the invention.
The general characteristics of the separate optical and electronic devices, which are to be integrated, are hereinafter considered with reference to figures 1 and 2.
The necessary layers to form an optical waveguide for the switch/modulator are, as shown schematically in figure 1, a high refractive index semiconductor layer forming the waveguide core 1 and upper 2 and lower 3 cladding layers of lower refractive index semiconductor. For the purpose of illustration a device operating at 1.3 or 1.55 llm wavelength might employ InP for layers 2 and 3 and an InGaAsP alloy with bandgap =1.15 Rm for layer 1. The heterostructure provides the vertical confinement of the optical waveguide mode. Lateral confinement may be achieved by etching a rib 4 into the upper semiconductor layer. A p-doped layer 5 and an n-doped layer 6 permit a high electrical field to be established in the region encompassing the guided optical mode.A metal contact is formed on the surface of the p-layer 5, while in a discrete device the metal n-contact may be on the lower surface of the n-region 6.
Alternatively a contact may be provided on the top surface of the layer 6 after local etching to reveal this layer, or elsewhere. The application of a reverse voltage to this PIN structure results in phase modulation of the optical wave via the electro-optic effect. Optical intensity modulation and space switching functions are achieved by incorporating the above waveguide in well known integrated optical device structures such as the Mach-Zehnder interferometer and the directional coupler switch. The particular waveguide layouts needed for these functions are not essential to the present invention.
A typical structure for a heterojunction bipolar transistor is shown schematically in figure 2. The necessary layers are an emitter 7, base 8 and collector 9. A further layer 1 with appropriate doping may also be included for the collector contact. The central base layer has opposite doping with respect to that of the emitter and collector.
In the example discussed here, the composition of this layer is chosen to provide a narrower (longer wavelength) band gap, which inhibits the injection of holes from the emitter layer into the base and thus improves the current gain. Electrical contact is provided to all three sections by established etching and metal deposition processes.
Referring to figure 3 which illustrates an embodiment of the present invention a plurality of successive epitaxial semiconductor layers (first, second, third, fourth and fifth) are formed on a substrate 14. These epitaxial layers are selectively etched to form a first structure of the HBT and a second structure of the waveguide device. The second, third and fourth epitaxial layers provide the collector layer 9 of the transistor and the waveguide core 1 with lower and upper cladding layers 2 and 3 of the waveguide device.
The first epitaxial layer provides the contact layer 6 of the waveguide device and the collector contact layer 10 of the transistor.
The fifth epitaxial layer provides the contact layer 5 of the waveguide device and the base 8 of the transistor . The emitter layer 7 is formed on the base 8.
The embodiment of the invention illustrated with reference to figure 3, preferably employs device elements with the following characteristics in order to achieve compatibility with respect to semiconductor layer structures while maintaining satisfactory device performance: ~ All of the layers within the optical waveguide structure have
band gap wavelengths less than the operating wavelength of
the switch, in order to minimise direct transitions giving rise to
absorption of the optical wave.
~ The guiding core 1 and cladding layers 2, 3 of the waveguide
are formed with low doping levels to further reduce the optical
absorption. The material forming the waveguide core layer 1
will have narrower band gap than that of the cladding: for
example in a device for 1 .3#m or 1 .55#m operation the core
may be of InGaAsP (hg - 1.15cm) and the cladding may be InP.
In the integrated structure these layers are incorporated into
the collector region 9 of the transistor and are grown upon a
highly doped n layer 10,6 to accommodate the electrical
contacts 12,13.
~ The entire structure is formed upon a substrate or layer 14 of
semi-insulating semiconductor material, so that electrical
isolation may be achieved as required by etching through the
lower contact layer of both the transistor and the optical switch.
The same material composition is employed for the transistor
base region 8 and for the upper contact layer 5 of the optical
switch. This layer has a narrower band gap than the
immediately adjacent emitter and collector layers within the
transistor structure. For example in a device based upon InP, a
layer of the alloy InGaAsP (kgX l.l5pm) may be employed.
This layer may carry an appropriately high doping to facilitate
its use as a contact layer; high transistor gain is maintained as a
result of the blocking character of the heterojunction.
Electrical contacts 16, 15 and 12 to the emitter 7, base 8 and
collector 9 of the transistor are achieved by etching a suitable profile
to expose the layers and by the subsequent deposition of appropriate
metallisation. Electrical contact to the n-doped lower layer of the
switch 13 may be made in the same way as to the collector contact
12 of the transistor.
The validity of the approach described here has been verified
by computer simulation and by experiments in which transistors and
electro-optic directional coupler switches were fabricated using
common specifications for the semiconductor layers forming the
devices. Preliminary results indicate that the gain and the
breakdown voltage of the transistor are sufficient to provide the
driving voltage for the switch from standard electronic logic levels
inputs. In particular breakdown voltage > 20V and gain > 200 have
been achieved in the transistor, along with an optical switch
operating voltage of 20V.
Claims (9)
1. A method of forming a monolithic integrated structure including a hetrojunction bipolar transistor and an optical waveguide device which method comprises forming on a substrate a plurality of successive epitaxial semiconductor layers, said layers being selectively etched to provide on said substrate a first structure of said transistor and a second structure of said waveguide device.
2. A method as claimed in claim 1, in which said plurality of layers include first, second, third, fourth and fifth epitaxial layers, said third layer providing a waveguide core layer of the waveguide device, said second and fourth layers providing lower and upper cladding layers for the core layer, the cladding layers being of a lower refractive index than the core layer and said first and third layers providing contact layers of the waveguide device.
3. A method as claimed in claim 2, in which said etching of said layers includes etching a rib into the fourth and fifth layers of said waveguide device.
4. A method as claimed in claim 2 or 3, in which said second, third and fourth epitaxial layers provide a collector for said transistor, said fifth epitaxial layer provides a base of said transistor and said first epitaxial layer provides a contact layer for the transistor, said method further comprising providing an emitter on said base of the transistor.
5. A method as claimed in any one of claims 2 to 4, in which said fifth layer has a doping opposite to the doping of the first, second third and fourth layer.
6. A method as claimed in any one of the preceding claims, in which said plurality of layers are formed of a material selected from
InP, InGaAsP, InGaAs, InGaAlAs, GaAs and AlGaAs.
7. A method as claimed in any one of the preceding claims, in which said substrate is a layer of InP, GaAs or Si.
8. A method of forming a monolithic integrated structure substantially as hereinbefore described with reference to figure 3 of the accompanying drawings.
9. A monolithic integrated structure made by the method claimed in any one the of the preceding claims.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9008880A GB2243241B (en) | 1990-04-20 | 1990-04-20 | Heterojunction bipolar transistor and optical waveguide device for monolithic integration |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9008880A GB2243241B (en) | 1990-04-20 | 1990-04-20 | Heterojunction bipolar transistor and optical waveguide device for monolithic integration |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9008880D0 GB9008880D0 (en) | 1990-06-20 |
| GB2243241A true GB2243241A (en) | 1991-10-23 |
| GB2243241B GB2243241B (en) | 1994-03-16 |
Family
ID=10674711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9008880A Expired - Fee Related GB2243241B (en) | 1990-04-20 | 1990-04-20 | Heterojunction bipolar transistor and optical waveguide device for monolithic integration |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2243241B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2270418A (en) * | 1992-09-04 | 1994-03-09 | Tektronix Inc | Implant-free heterojunction bipolar transistor integrated circuit process |
| WO2003023469A1 (en) * | 2001-09-10 | 2003-03-20 | California Institue Of Technology | Strip loaded waveguide integrated with electronics components |
| US6839488B2 (en) | 2001-09-10 | 2005-01-04 | California Institute Of Technology | Tunable resonant cavity based on the field effect in semiconductors |
| US6870977B2 (en) * | 2001-02-15 | 2005-03-22 | Avanex Corporation | Monolithic integrated optical component including a modulator and a heterojunction bipolar transistor |
| EP1367651A3 (en) * | 2002-05-31 | 2005-07-06 | Electronics and Telecommunications Research Institute | Photoreceiver for selectively detecting light of a specific wavelength and the method of manufacturing the same |
| US7072556B1 (en) | 2002-06-24 | 2006-07-04 | Luxtera, Inc. | CMOS process active waveguides |
| US7082235B2 (en) | 2001-09-10 | 2006-07-25 | California Institute Of Technology | Structure and method for coupling light between dissimilar waveguides |
| US7826688B1 (en) | 2005-10-21 | 2010-11-02 | Luxtera, Inc. | Enhancing the sensitivity of resonant optical modulating and switching devices |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117747691B (en) * | 2023-11-22 | 2024-08-13 | 广州市南沙区北科光子感知技术研究院 | Bicolor barrier type GaSb-based InAs/InAsSb heterojunction photoelectric transistor and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0129477A1 (en) * | 1983-06-17 | 1984-12-27 | David Ankri | Double heterojunction bipolar transistor suited for monolithic integration with optoelectronic devices |
| GB2162688A (en) * | 1984-07-31 | 1986-02-05 | Sharp Kk | Optical semiconductor apparatus |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4899200A (en) * | 1988-06-03 | 1990-02-06 | Regents Of The University Of Minnesota | Novel high-speed integrated heterostructure transistors, photodetectors, and optoelectronic circuits |
-
1990
- 1990-04-20 GB GB9008880A patent/GB2243241B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0129477A1 (en) * | 1983-06-17 | 1984-12-27 | David Ankri | Double heterojunction bipolar transistor suited for monolithic integration with optoelectronic devices |
| GB2162688A (en) * | 1984-07-31 | 1986-02-05 | Sharp Kk | Optical semiconductor apparatus |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4329189A1 (en) * | 1992-09-04 | 1994-03-10 | Tektronix Inc | Process for the implant-free production of integrated circuits consisting of bipolar transistors with heterojunction |
| GB2270418A (en) * | 1992-09-04 | 1994-03-09 | Tektronix Inc | Implant-free heterojunction bipolar transistor integrated circuit process |
| US6870977B2 (en) * | 2001-02-15 | 2005-03-22 | Avanex Corporation | Monolithic integrated optical component including a modulator and a heterojunction bipolar transistor |
| US6895148B2 (en) | 2001-09-10 | 2005-05-17 | California Institute Of Technology | Modulator based on tunable resonant cavity |
| US6839488B2 (en) | 2001-09-10 | 2005-01-04 | California Institute Of Technology | Tunable resonant cavity based on the field effect in semiconductors |
| US6834152B2 (en) | 2001-09-10 | 2004-12-21 | California Institute Of Technology | Strip loaded waveguide with low-index transition layer |
| WO2003023469A1 (en) * | 2001-09-10 | 2003-03-20 | California Institue Of Technology | Strip loaded waveguide integrated with electronics components |
| US6917727B2 (en) | 2001-09-10 | 2005-07-12 | California Institute Of Technology | Strip loaded waveguide integrated with electronics components |
| US6990257B2 (en) | 2001-09-10 | 2006-01-24 | California Institute Of Technology | Electronically biased strip loaded waveguide |
| US7082235B2 (en) | 2001-09-10 | 2006-07-25 | California Institute Of Technology | Structure and method for coupling light between dissimilar waveguides |
| EP1367651A3 (en) * | 2002-05-31 | 2005-07-06 | Electronics and Telecommunications Research Institute | Photoreceiver for selectively detecting light of a specific wavelength and the method of manufacturing the same |
| US7072556B1 (en) | 2002-06-24 | 2006-07-04 | Luxtera, Inc. | CMOS process active waveguides |
| US7218826B1 (en) | 2002-06-24 | 2007-05-15 | Luxtera, Inc. | CMOS process active waveguides on five layer substrates |
| US7826688B1 (en) | 2005-10-21 | 2010-11-02 | Luxtera, Inc. | Enhancing the sensitivity of resonant optical modulating and switching devices |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2243241B (en) | 1994-03-16 |
| GB9008880D0 (en) | 1990-06-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5703895A (en) | Opto-electronic semiconductor device including an integrated mode transformer | |
| US4997246A (en) | Silicon-based rib waveguide optical modulator | |
| US9625648B2 (en) | Method for fabricating a monolithic optoelectronic device | |
| US6479844B2 (en) | Modulation doped thyristor and complementary transistor combination for a monolithic optoelectronic integrated circuit | |
| US5125065A (en) | Integrated optical arrangement having at least one optical waveguide integrated on a substrate of a semiconductor material and the method of manufacture | |
| US6229189B1 (en) | Multi-function optoelectronic device structure | |
| US10302861B2 (en) | Semiconductor optical apparatus | |
| GB2243241A (en) | Heterojunction bipolar transistor and optical waveguide device for monolithic integration | |
| JPH0738457B2 (en) | Opto-electronic bistable element | |
| US4082419A (en) | Optical waveguide couplers | |
| GB2436397A (en) | Monolithically integrated optoelectronic components | |
| US4862474A (en) | Semicondutor laser device | |
| US6870977B2 (en) | Monolithic integrated optical component including a modulator and a heterojunction bipolar transistor | |
| CA2051453C (en) | Long wavelength transmitter opto-electronic integrated circuit | |
| US5104823A (en) | Monolithic integration of optoelectronic and electronic devices | |
| JPH04232926A (en) | Optoelectronic switching circuit | |
| US6215935B1 (en) | Optical component based on semi-conductor optical amplifiers having a reduced number of independent electrodes | |
| Schneider et al. | Monolithically integrated optoelectronic circuits using HBT, EAM, and TEAT | |
| US5028108A (en) | Bipolar transistor including optical waveguide | |
| Huelsman | Development of Circuits in Indium Phosphide for Communication at 40Gbit/s and Above. | |
| Yamaguchi et al. | InGaAsP carrier injection modulator integrated with DFB LD | |
| Reimann et al. | Integration of heterostructure bipolar transistor and electroabsorption waveguide modulator based on a multifunctional layer design for 1.55/spl mu/m | |
| JPS6113222A (en) | Integrated waveguide type optical element | |
| Shaw et al. | Optoelectronic integration of optical switching devices for telecommunications | |
| JPH06132511A (en) | Photodetecting integrated element |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19970420 |