Pub Date : 1978-09-01DOI: 10.1049/IJ-SSED:19780047
J. C. Plunkett, J. Stone, A. Hyslop
This paper describes the effect of recombination in the external base and epitaxial regions on the inverse current gain and related parameters of the n+pnn+ bipolar transistor. It is shown that the inverse current gain increases with the decrease in recombination in the external base region by use of the doublebase process. Improvement of the inverse gain is also shown with a decrease in epitaxial-layer thickness until it reaches a point of diminishing return at about one micrometre width between the space-charge regions. Breakdown phenomena related to the external base depth and the epitaxial layer thickness are also discussed.
{"title":"Some aspects of inverse bipolar transistor improvement through recombination reduction","authors":"J. C. Plunkett, J. Stone, A. Hyslop","doi":"10.1049/IJ-SSED:19780047","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780047","url":null,"abstract":"This paper describes the effect of recombination in the external base and epitaxial regions on the inverse current gain and related parameters of the n+pnn+ bipolar transistor. It is shown that the inverse current gain increases with the decrease in recombination in the external base region by use of the doublebase process. Improvement of the inverse gain is also shown with a decrease in epitaxial-layer thickness until it reaches a point of diminishing return at about one micrometre width between the space-charge regions. Breakdown phenomena related to the external base depth and the epitaxial layer thickness are also discussed.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124949031","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 : 1978-07-01DOI: 10.1049/IJ-SSED:19780040
W. Platte,
Laser-controlled solid-state microstrip switches using a gap and a shunt structure in tandem offer the advantage of employing optical sources over a wide spectrum range. The spectral response of such an optoelectronic switch is mainly determined by the spectral dependence of power transmission through the illuminated semiconductor gap region. The physical and electronic processes within the excited semiconductor region are analysed quantitatively with special regard to the required high-speed laser pulse excitation. The corresponding effects on the microwave power transmission of the switch are studied successfully by using a simple π equivalent circuit. This equivalent circuit consists of several gap and shunt conductances that depend on the incident optical energy and on the optical wavelength of the controlling laser pulses. The optical bandwidth of the device is discussed with special regard to the long-wavelength cutoff, which, in this case, is determined by the specific functioning of the switch rather than by the decrease in photosensitivity. The analytical results are specified for a high-resistivity silicon substrate used in the corresponding experiments. Theoretical and experimental results were found to agree fairly well.
{"title":"Spectral dependence of microwave power transmission in laser-controlled solid-state microstrip switches","authors":"W. Platte,","doi":"10.1049/IJ-SSED:19780040","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780040","url":null,"abstract":"Laser-controlled solid-state microstrip switches using a gap and a shunt structure in tandem offer the advantage of employing optical sources over a wide spectrum range. The spectral response of such an optoelectronic switch is mainly determined by the spectral dependence of power transmission through the illuminated semiconductor gap region. The physical and electronic processes within the excited semiconductor region are analysed quantitatively with special regard to the required high-speed laser pulse excitation. The corresponding effects on the microwave power transmission of the switch are studied successfully by using a simple π equivalent circuit. This equivalent circuit consists of several gap and shunt conductances that depend on the incident optical energy and on the optical wavelength of the controlling laser pulses. The optical bandwidth of the device is discussed with special regard to the long-wavelength cutoff, which, in this case, is determined by the specific functioning of the switch rather than by the decrease in photosensitivity. The analytical results are specified for a high-resistivity silicon substrate used in the corresponding experiments. Theoretical and experimental results were found to agree fairly well.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133635484","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 : 1978-07-01DOI: 10.1049/IJ-SSED.1978.0042
S. Jindal, A. Bhattacharyya, J. Warrior
A two-dimensional analysis of planar p-n-n+ junctions has been carried out using a successive-point overrelaxation method. This analysis gives better insight into the location of breakdown and the dependence of breakdown voltage on physical parameters of the junction, than obtained by a one-dimensional analysis. During the study an empirical relation has been found between breakdown voltage and the corresponding depletion-layer width. The computer program developed in this work enables calculation of generation current also. The information obtained helps in better device design.
{"title":"Two-dimensional analysis of breakdown in epitaxial planar junctions","authors":"S. Jindal, A. Bhattacharyya, J. Warrior","doi":"10.1049/IJ-SSED.1978.0042","DOIUrl":"https://doi.org/10.1049/IJ-SSED.1978.0042","url":null,"abstract":"A two-dimensional analysis of planar p-n-n+ junctions has been carried out using a successive-point overrelaxation method. This analysis gives better insight into the location of breakdown and the dependence of breakdown voltage on physical parameters of the junction, than obtained by a one-dimensional analysis. During the study an empirical relation has been found between breakdown voltage and the corresponding depletion-layer width. The computer program developed in this work enables calculation of generation current also. The information obtained helps in better device design.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123341736","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 : 1978-07-01DOI: 10.1049/IJ-SSED:19780043
A. Vanoverschelde, G. Salmer
The capabilities of the silicon baritt device in the millimetre wavelength range are presented. Analytical treatment shows that the positive resistance of the forward-biased zone is a fundamental limitation of the device operation. An exact large-signal numerical simulation, based on a single-carrier model, which takes into account carrier velocity modulation, the diffusion effect and realistic doping profile, enables us to illustrate the basic transport mechanisms involved in the device, chiefly the dynamic behaviour of the emission zonewidth. The effects of doping profile and material parameters on the device performances are considered for a frequency of 40 GHz. A high doping concentration near the injection plane is required to limit the positive resistance, and computed results indicate an optimum-doping spike value. An optimum efficiency of 3% and oscillation powers exceeding 20 mW for a device area of 10?5 cm2 are obtained with structures specified in the text. However, series-loss resistances have to be reduced as far as possible to maintain oscillation. Output power falls to 8 mW for a minimal series resistance estimated at 0.5?
{"title":"Silicon baritt diodes as millimetre wavelength oscillators","authors":"A. Vanoverschelde, G. Salmer","doi":"10.1049/IJ-SSED:19780043","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780043","url":null,"abstract":"The capabilities of the silicon baritt device in the millimetre wavelength range are presented. Analytical treatment shows that the positive resistance of the forward-biased zone is a fundamental limitation of the device operation. An exact large-signal numerical simulation, based on a single-carrier model, which takes into account carrier velocity modulation, the diffusion effect and realistic doping profile, enables us to illustrate the basic transport mechanisms involved in the device, chiefly the dynamic behaviour of the emission zonewidth. The effects of doping profile and material parameters on the device performances are considered for a frequency of 40 GHz. A high doping concentration near the injection plane is required to limit the positive resistance, and computed results indicate an optimum-doping spike value. An optimum efficiency of 3% and oscillation powers exceeding 20 mW for a device area of 10?5 cm2 are obtained with structures specified in the text. However, series-loss resistances have to be reduced as far as possible to maintain oscillation. Output power falls to 8 mW for a minimal series resistance estimated at 0.5?","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123773799","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 : 1978-07-01DOI: 10.1049/IJ-SSED:19780045
R. Startin
Full computer analysis of the time-varying behaviour of semiconductor devices tends to be very expensive. The ‘small-signal’ method is much cheaper. It may be the only practical option, and in any case is a useful first step. Sometimes, the response of the small-signal analysis to a small parameter change is of interest (e.g. to find the temperature coefficient of an oscillator). Two runs at slightly different values of the parameter may not work, because of truncation errors. A perturbation approach that is cheaper to run and guarantees accuracy is described.
{"title":"Perturbing a parameter in a 'small-signal' device simulation","authors":"R. Startin","doi":"10.1049/IJ-SSED:19780045","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780045","url":null,"abstract":"Full computer analysis of the time-varying behaviour of semiconductor devices tends to be very expensive. The ‘small-signal’ method is much cheaper. It may be the only practical option, and in any case is a useful first step. Sometimes, the response of the small-signal analysis to a small parameter change is of interest (e.g. to find the temperature coefficient of an oscillator). Two runs at slightly different values of the parameter may not work, because of truncation errors. A perturbation approach that is cheaper to run and guarantees accuracy is described.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122374158","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 : 1978-07-01DOI: 10.1049/IJ-SSED:19780041
P. Ladbrooke, R. S. Huang, J. Barnard
An m.o.s. technique is described for making free-carrier profile measurements on thin layers using a current pulse of a few microseconds duration. The method minimises distortion of the results due to surface states and enables the profile right up to the semiconductor surface to be determined
{"title":"Fast current pulse m.o.s. deep-depletion technique for profiling thin epitaxial and ion-implanted layers","authors":"P. Ladbrooke, R. S. Huang, J. Barnard","doi":"10.1049/IJ-SSED:19780041","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780041","url":null,"abstract":"An m.o.s. technique is described for making free-carrier profile measurements on thin layers using a current pulse of a few microseconds duration. The method minimises distortion of the results due to surface states and enables the profile right up to the semiconductor surface to be determined","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133840287","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 : 1978-06-01DOI: 10.1049/IJ-SSED:19780032
R. Hill
The theoretical and experimental studies of thin-film solar cells carried out at Newcastle Polytechnic are described. A theoretical model has been developed in which optical interference effects lead to improved photocurrents at small thicknesses of the Cu2S or CuInSe2 absorbing layers, and the optical properties of the substrate can have a significant effect on the photocurrent. The results for CdS/Cu2S and CdS/CuInSe2 junctions are presented, and it is found that the optimum thickness of the absorbing layer is 0.1-0.15?m in both cases. The dry-barrier technique for producing CdS/Cu2S junctions has been investigated in some detail, and the techniques that have been developed are described. Most of our work with the dry-barrier technique has used thermally evaporated cadmium sulphide, and the efficiency of these cells is estimated to be up to 6%. The more recent work on junction formation on sputtered cadmium sulphide is also described breifly.
{"title":"Thin-film solar cells produced by physical vapour deposition","authors":"R. Hill","doi":"10.1049/IJ-SSED:19780032","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780032","url":null,"abstract":"The theoretical and experimental studies of thin-film solar cells carried out at Newcastle Polytechnic are described. A theoretical model has been developed in which optical interference effects lead to improved photocurrents at small thicknesses of the Cu2S or CuInSe2 absorbing layers, and the optical properties of the substrate can have a significant effect on the photocurrent. The results for CdS/Cu2S and CdS/CuInSe2 junctions are presented, and it is found that the optimum thickness of the absorbing layer is 0.1-0.15?m in both cases. The dry-barrier technique for producing CdS/Cu2S junctions has been investigated in some detail, and the techniques that have been developed are described. Most of our work with the dry-barrier technique has used thermally evaporated cadmium sulphide, and the efficiency of these cells is estimated to be up to 6%. The more recent work on junction formation on sputtered cadmium sulphide is also described breifly.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114745982","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 : 1978-06-01DOI: 10.1049/IJ-SSED:19780027
J.I.B. Wilson, J. Mcgill
M.I.S. solar cells of amorphous silicon on stainless steel, with a top barrier contact of Ni/TiOx, have given 4.8% power conversion efficiency without an antireflection coating. The insulating layer, with an optimum thickness of ? 2nm, compensates for the low work function of nickel compared with platinum, and enables similar high open-circuit voltages (up to 680 mV) to be obtained. The fill factor is not appreciably degraded by the addition of an insulating layer, unless this is thicker than = 3 nm. Under illumination, the diode characteristics change compared with their behaviour in the dark; the diode factor, the barrier height, and the series resistance are all dependent on light intensity.
{"title":"Amorphous-silicon m.i.s. solar cells","authors":"J.I.B. Wilson, J. Mcgill","doi":"10.1049/IJ-SSED:19780027","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780027","url":null,"abstract":"M.I.S. solar cells of amorphous silicon on stainless steel, with a top barrier contact of Ni/TiOx, have given 4.8% power conversion efficiency without an antireflection coating. The insulating layer, with an optimum thickness of ? 2nm, compensates for the low work function of nickel compared with platinum, and enables similar high open-circuit voltages (up to 680 mV) to be obtained. The fill factor is not appreciably degraded by the addition of an insulating layer, unless this is thicker than = 3 nm. Under illumination, the diode characteristics change compared with their behaviour in the dark; the diode factor, the barrier height, and the series resistance are all dependent on light intensity.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125642213","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 : 1978-06-01DOI: 10.1049/IJ-SSED:19780028
D. H. Mash, P. Ross
The paper describes a solar-electric conversion module which uses a plastic Fresnel lens to concentrate sunlight on to a group of GaAs/GaAlAs solar cells. These cells have given 16?20% conversion efficiency and are expected to maintain this at the high intensities and temperatures involved. The necessary ability to track the sun is achieved using a novel pneumatic system powered by solar energy. When the eyeball is misaligned, the sun's image falls on a heat exchanger in one of two air reservoirs adjacent to the cells. The resultant expansion forces a magnetised piston against a fixed external magnetic field, causing the complete module to rotate until the solar cells are again in the focus. There need be no mechanical linkage with the external world apart from electrical output leads, and hence the module can be hermetically sealed and floated on water to provide a cheap, reliable, low-friction bearing. No motors or clockwork drivers are needed. Several experimental 1-axis modules have been made, either floating on water or using conventional bearings. All demonstrated the required `seek? and `hold? capabilities, finding the sun in 2?10s. Work on a damping mechanism to prevent overshoot, and tests of the slow-tracking accuracy, are presently under way. An early 2-axis model on a demountable test bed has also been demonstrated, using four air chambers. The paper reports details of the magnetic piston, the optics of the system, and the thermodynamics of the heat exchangers, and an estimate of eventual costs.
{"title":"Solar eyeball: an automatic sun-tracking concentrator for use with photovoltaic generators","authors":"D. H. Mash, P. Ross","doi":"10.1049/IJ-SSED:19780028","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780028","url":null,"abstract":"The paper describes a solar-electric conversion module which uses a plastic Fresnel lens to concentrate sunlight on to a group of GaAs/GaAlAs solar cells. These cells have given 16?20% conversion efficiency and are expected to maintain this at the high intensities and temperatures involved. The necessary ability to track the sun is achieved using a novel pneumatic system powered by solar energy. When the eyeball is misaligned, the sun's image falls on a heat exchanger in one of two air reservoirs adjacent to the cells. The resultant expansion forces a magnetised piston against a fixed external magnetic field, causing the complete module to rotate until the solar cells are again in the focus. There need be no mechanical linkage with the external world apart from electrical output leads, and hence the module can be hermetically sealed and floated on water to provide a cheap, reliable, low-friction bearing. No motors or clockwork drivers are needed. Several experimental 1-axis modules have been made, either floating on water or using conventional bearings. All demonstrated the required `seek? and `hold? capabilities, finding the sun in 2?10s. Work on a damping mechanism to prevent overshoot, and tests of the slow-tracking accuracy, are presently under way. An early 2-axis model on a demountable test bed has also been demonstrated, using four air chambers. The paper reports details of the magnetic piston, the optics of the system, and the thermodynamics of the heat exchangers, and an estimate of eventual costs.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124490437","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 : 1978-06-01DOI: 10.1049/IJ-SSED:19780022
T. Coutts, K. Lawson
For photovoltaic collector arrays, heterojunction devices should be studied more extensively. The advantages of the InP/CdS cell are outlined, both as single-crystal InP with deposited CdS and as an all-thinfilm cell. Present work on the single-crystal InP with sputter-deposited CdS is described, and plans are given for polycrystalline thin films using r.f. sputtering.
{"title":"p-Inp/n-CdS heterojunction solar cells","authors":"T. Coutts, K. Lawson","doi":"10.1049/IJ-SSED:19780022","DOIUrl":"https://doi.org/10.1049/IJ-SSED:19780022","url":null,"abstract":"For photovoltaic collector arrays, heterojunction devices should be studied more extensively. The advantages of the InP/CdS cell are outlined, both as single-crystal InP with deposited CdS and as an all-thinfilm cell. Present work on the single-crystal InP with sputter-deposited CdS is described, and plans are given for polycrystalline thin films using r.f. sputtering.","PeriodicalId":127114,"journal":{"name":"Iee Journal on Solidstate and Electron Devices","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127533678","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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