Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493686
M. Bourke, K. Hilton, M. Crouch, M. Kane, N. Borsing, T. Russell
Reactive ion etching is becoming increasingly widespread in the fabrication of III-V semiconductor devices. Particular applications include optical waveguides, heterojunction bipolar transistors (HBTs) and FET/HEMT type devices. Etch depth control is a critical issue in the fabrication of many devices. Optical waveguides require accurate etch depths for optical mode control whereas in the fabrication of HBTs there is a requirement to access a thin base layer. It is possible to fabricate devices using a "dead reckoning" method-however, this has proved not to be very accurate and a form of end point detection is required. A number of end point detection techniques are available and include optical emission spectroscopy, optical reflectometry and mass spectroscopy. This paper will compare all three methods and demonstrate weaknesses and strong points for each. Particular attention will be given to optical reflectometry and mass spectroscopy in the fabrication of HBTs.
{"title":"The application of end point detection in the fabrication of optical and microwave devices","authors":"M. Bourke, K. Hilton, M. Crouch, M. Kane, N. Borsing, T. Russell","doi":"10.1109/EDMO.1995.493686","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493686","url":null,"abstract":"Reactive ion etching is becoming increasingly widespread in the fabrication of III-V semiconductor devices. Particular applications include optical waveguides, heterojunction bipolar transistors (HBTs) and FET/HEMT type devices. Etch depth control is a critical issue in the fabrication of many devices. Optical waveguides require accurate etch depths for optical mode control whereas in the fabrication of HBTs there is a requirement to access a thin base layer. It is possible to fabricate devices using a \"dead reckoning\" method-however, this has proved not to be very accurate and a form of end point detection is required. A number of end point detection techniques are available and include optical emission spectroscopy, optical reflectometry and mass spectroscopy. This paper will compare all three methods and demonstrate weaknesses and strong points for each. Particular attention will be given to optical reflectometry and mass spectroscopy in the fabrication of HBTs.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128491079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493711
M. McCullagh, J. Moult, R. Davies, B. Wallis, S. Wadsworth
A new GaAs HBT process has been developed at GMMT for the implementation of high performance microwave and optical sub-systems. Two versions of the process exist: B20 for small signal and digital applications and B20P for microwave power applications. 1/2 static frequency dividers have been designed on the process which toggle at frequencies up to 17 GHz. X-band power MMICs operating over a bandwidth of 9 to 12 GHz deliver an output power of 2 W with a power added efficiency of 30% and associated gain of 14 dB. The unique characteristics of excellent power performance, low 1/f noise and wideband operation will ensure that GaAs HBTs act as a key enabling technology for meeting the ever increasing demands of wireless and optical systems.
{"title":"An overview of high frequency circuit design on the GMMT GaAs HBT process","authors":"M. McCullagh, J. Moult, R. Davies, B. Wallis, S. Wadsworth","doi":"10.1109/EDMO.1995.493711","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493711","url":null,"abstract":"A new GaAs HBT process has been developed at GMMT for the implementation of high performance microwave and optical sub-systems. Two versions of the process exist: B20 for small signal and digital applications and B20P for microwave power applications. 1/2 static frequency dividers have been designed on the process which toggle at frequencies up to 17 GHz. X-band power MMICs operating over a bandwidth of 9 to 12 GHz deliver an output power of 2 W with a power added efficiency of 30% and associated gain of 14 dB. The unique characteristics of excellent power performance, low 1/f noise and wideband operation will ensure that GaAs HBTs act as a key enabling technology for meeting the ever increasing demands of wireless and optical systems.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"18 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125540041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493701
S. Greaves, R. Unwin
For complete characterisation of the noise performance of FET type structures, such as MESFETs and HEMTs, accurate values for the device's intrinsic noise parameters are required. These parameters have been shown to be sensibly frequency independent below 30 GHz but are strongly bias dependent. The problem of accurate determination of the intrinsic noise parameters for GaAs devices is complicated by the carrier transport mechanisms that exist in such material. This is particularly true for sub-micron gate-length devices where channel field strengths are far in excess of the critical field required for velocity saturation of the carriers. As yet no analytic solution is available that can accurately predict the current dependency of the intrinsic noise parameters of such devices. Here results obtained from measured noise data are presented that show the evolution of these parameters with drain current for two practical devices.
{"title":"The influence of bias conditions upon the intrinsic noise parameters of short gate length GaAs MESFETs","authors":"S. Greaves, R. Unwin","doi":"10.1109/EDMO.1995.493701","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493701","url":null,"abstract":"For complete characterisation of the noise performance of FET type structures, such as MESFETs and HEMTs, accurate values for the device's intrinsic noise parameters are required. These parameters have been shown to be sensibly frequency independent below 30 GHz but are strongly bias dependent. The problem of accurate determination of the intrinsic noise parameters for GaAs devices is complicated by the carrier transport mechanisms that exist in such material. This is particularly true for sub-micron gate-length devices where channel field strengths are far in excess of the critical field required for velocity saturation of the carriers. As yet no analytic solution is available that can accurately predict the current dependency of the intrinsic noise parameters of such devices. Here results obtained from measured noise data are presented that show the evolution of these parameters with drain current for two practical devices.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132881031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493698
S. Bashar, A. Rezazadeh
The electrical, optical and spectral responses of optically transparent emitter InP/InGaAs heterojunction phototransistors (HPTs) fabricated using Indium Tin Oxide (ITO) are presented. These HPTs showed significantly increased optical responsivities while: the electrical characteristics were similar to their respective opaque counterparts. Responsivities of 28 A/W at 1310 nm for the InP/InGaAs HPTs were obtained. The spectral responses of these phototransistors were simulated and compared with the measured results and good correlation between the experiments and the theoretical models were obtained.
{"title":"Characterisation of transparent ITO emitter contact InP/InGaAs heterojunction phototransistors","authors":"S. Bashar, A. Rezazadeh","doi":"10.1109/EDMO.1995.493698","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493698","url":null,"abstract":"The electrical, optical and spectral responses of optically transparent emitter InP/InGaAs heterojunction phototransistors (HPTs) fabricated using Indium Tin Oxide (ITO) are presented. These HPTs showed significantly increased optical responsivities while: the electrical characteristics were similar to their respective opaque counterparts. Responsivities of 28 A/W at 1310 nm for the InP/InGaAs HPTs were obtained. The spectral responses of these phototransistors were simulated and compared with the measured results and good correlation between the experiments and the theoretical models were obtained.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126064312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493685
J. Swanson, Q. Wang, M. Bowser
The static and dynamic behaviours of Si/sub 3/N/sub 4/-GaAs interfaces are described. The possible effects of the passivated surface on device behaviour are considered with relation to devices of current interest.
{"title":"The electronic behaviour of Si/sub 3/N/sub 4/-GaAs interfaces","authors":"J. Swanson, Q. Wang, M. Bowser","doi":"10.1109/EDMO.1995.493685","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493685","url":null,"abstract":"The static and dynamic behaviours of Si/sub 3/N/sub 4/-GaAs interfaces are described. The possible effects of the passivated surface on device behaviour are considered with relation to devices of current interest.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"249 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123162965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493691
B. Rahman, T. Wongcharoen, K. Grattan
The accurate characterization of directional coupler-based photonic devices is presented using the coupled mode and the least squares boundary residual approaches along with the finite element method. Results are obtained showing the power transfer ratio between such coupled waveguides, and they compare favourably with those of published data.
{"title":"Characterization of directional coupler-based optoelectronic devices","authors":"B. Rahman, T. Wongcharoen, K. Grattan","doi":"10.1109/EDMO.1995.493691","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493691","url":null,"abstract":"The accurate characterization of directional coupler-based photonic devices is presented using the coupled mode and the least squares boundary residual approaches along with the finite element method. Results are obtained showing the power transfer ratio between such coupled waveguides, and they compare favourably with those of published data.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124728970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493694
A. Al-Bustani, M. Feteha
A major task in future developments of GaAs space solar cells is to increase the power to area ratio. In this work, high performance in a new triple heterojunction AlGaAs-GaAs space solar cell is obtained by applying antireflection coating with optimum thicknesses. The effects of single and double antireflection coatings on the output characteristics are presented. The reflection from the multiple interfaces through the cell itself is taken into consideration in the optimisation calculations. The use of MgF/sub 2//ZnS as a double antireflection coating for the cell gives an efficiency of 22.101% at AM0.
{"title":"Design of antireflection coatings for triple heterojunction AlGaAs-GaAs space solar cells","authors":"A. Al-Bustani, M. Feteha","doi":"10.1109/EDMO.1995.493694","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493694","url":null,"abstract":"A major task in future developments of GaAs space solar cells is to increase the power to area ratio. In this work, high performance in a new triple heterojunction AlGaAs-GaAs space solar cell is obtained by applying antireflection coating with optimum thicknesses. The effects of single and double antireflection coatings on the output characteristics are presented. The reflection from the multiple interfaces through the cell itself is taken into consideration in the optimisation calculations. The use of MgF/sub 2//ZnS as a double antireflection coating for the cell gives an efficiency of 22.101% at AM0.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116420373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493688
K. Jones, K. Hilton, M. Crouch, B. T. Hughes, M. Cole, W. Han
Summary form only given. We compare the electrical, physical, and chemical properties of TiPdAu and PdGeTiPt contacts for GaAs HBTs. Contact and specific contact resistances are measured using the TLM method and devices made with the two different types of emitter contacts are compared, the surface structures are examined using optical and scanning electron microscopy, and the chemical structures are investigated with Auger and transmission electron microscopy. In addition, comparisons are made between the TiPdAu and PdGeTiPt contacts to heavily C-doped GaAs. The advantages of being able to substitute PdGeTiPt contacts for TiPdAu are that all of the contacts could be made with a single metallization, and the Pt would be a more effective diffusion barrier to the in-diffusion of Au.
{"title":"Analyses of ohmic contacts to GaAs based microwave HBTs","authors":"K. Jones, K. Hilton, M. Crouch, B. T. Hughes, M. Cole, W. Han","doi":"10.1109/EDMO.1995.493688","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493688","url":null,"abstract":"Summary form only given. We compare the electrical, physical, and chemical properties of TiPdAu and PdGeTiPt contacts for GaAs HBTs. Contact and specific contact resistances are measured using the TLM method and devices made with the two different types of emitter contacts are compared, the surface structures are examined using optical and scanning electron microscopy, and the chemical structures are investigated with Auger and transmission electron microscopy. In addition, comparisons are made between the TiPdAu and PdGeTiPt contacts to heavily C-doped GaAs. The advantages of being able to substitute PdGeTiPt contacts for TiPdAu are that all of the contacts could be made with a single metallization, and the Pt would be a more effective diffusion barrier to the in-diffusion of Au.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131930221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493695
D. Wake
InGaAs/InP heterojunction phototransistors are described which have a dc gain of several thousand and a frequency response that shows higher output power than optimised photodiodes at 40 GHz. This is accomplished as a result of the two-terminal, edge-coupled design approach, which allows small area devices to be fabricated with low parasitics and efficient optical access.
{"title":"Millimetre-wave InGaAs/InP heterojunction bipolar phototransistors","authors":"D. Wake","doi":"10.1109/EDMO.1995.493695","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493695","url":null,"abstract":"InGaAs/InP heterojunction phototransistors are described which have a dc gain of several thousand and a frequency response that shows higher output power than optimised photodiodes at 40 GHz. This is accomplished as a result of the two-terminal, edge-coupled design approach, which allows small area devices to be fabricated with low parasitics and efficient optical access.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131261452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493708
A. Borjak, P. Monteiro, I. Darwazeh, J. O'Reilly
This paper discusses the use of distributed amplifiers as transversal filters for high bit rate pulse shaping/filtering applications. Two schemes demonstrating a general approach, obtained by optimising one or more transversal filter parameters are explored. Simulation results, based on the parameters of a commercially available 40 GHz HEMT foundry process, are presented to illustrate the practicability of the different schemes.
{"title":"Distributed amplifiers with embedded signal shaping for multigigabit transmission systems","authors":"A. Borjak, P. Monteiro, I. Darwazeh, J. O'Reilly","doi":"10.1109/EDMO.1995.493708","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493708","url":null,"abstract":"This paper discusses the use of distributed amplifiers as transversal filters for high bit rate pulse shaping/filtering applications. Two schemes demonstrating a general approach, obtained by optimising one or more transversal filter parameters are explored. Simulation results, based on the parameters of a commercially available 40 GHz HEMT foundry process, are presented to illustrate the practicability of the different schemes.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125547500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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