1997 Fiscal Year Final Research Report Summary
Disordering by Diffusion of Impurities in InGaAs/AlGa/GaAs Multiple Layrs and Its Application to Vertical Cavity Surface Emitting Micro Lasers
| Project/Area Number |
08455168
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | Osaka Electro-Communication University |
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Principal Investigator |
SUSAKI Wataru Osaka Electro-Communication University, Dept.of Electronics, Professor., 工学部・電子工学科, 教授 (00268294)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUURA Hideharu Osaka Electro-Communication University, Dept.of Electronics, Lecturer., 工学部・電子工学科, 専任講師 (60278588)
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| Project Period (FY) |
1996 – 1997
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| Keywords | micro laser / heterostructure / strained quantum well / InGaAs / surface emitting / disorder / diffusion / multiple reflecting film |
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| Research Abstract |
Conventional surface emitting laser is usually fabricated by mesa etching to reduce threshold current, and the electrode is formed on the part of the light emitting surface. These difficulties to integrate electrical elemental devices such as FETs and also reduce the area of the laser, which is not desirable for high density integration OEIC and 2 dimensional laser array monolithic chips.
In the study, a novel structure based on TJS planar laser formed on semi-insulating substrate are proposed for the planar micro surface emitting laser fabricated by impurity disordering in superlattices. The main results obtained are as follows.
(1) A novel structure for a planar micro surface emitting laser : The laser structure has lateral conducting n and p layrs, which is inserted between GaAs/InGaAs/GaAs strained quantum well layrs and AlAs/GaAs DBR multiple reflector layrs in the TJS laser structure. Carrier injection is uniform in the quantum wells which overcomes the Joule heating due to high se
… More
ries resistance through hetero barriers of AlGaAs/GaAs multiple reflectors as found in conventional structures.
(2) Fabrication of the layr structure of the laser by MBE with water cooling method : The layr structure of the laser is strained single quantum well GaAs/InGaAs/GaAs sandwiched with 24 AlAs/GaAs quarter wavelength DBRs, which are formed by computer controlled MBE system with water cooling (not using liquid nitrogen cooling as in conventional one). A high efficient 0.98 mum photoluminescence for 8nm thick In_<0.2>Ga_<0.8>As is observed at room temperatire comparable with those of MOCVD growth.
(3) Diffusion of Si and Zn under As pressure : Zn and Si are chosen as the impurities for disordering of the superlattices. The films for diffusion are deposited on wafers by electron beam from SiO_2 contained Zn or pure Si. After deposition, the wafers are annealed at 600 C for Zn and 850 C for Si diffusion. It is found that Si diffusion is enhanced under As pressure in an evacuated quartz tube, and the diffusion depth is 4mum for 20 hr at 850C.
(4) Doping of conducting p and n GaAs layrs : n type conducting layrs by Si dopant and p type consuction layrs by Be doping are grown by the MBE,and the electron mobility exceed 2000 cm^2/V・s for typical donor conncenntration of 7x10^<17> cm^<-3> with the background other impurities less than 1x10^<17> cm^<-3>. Hole mobilities of Be-doping wafers are almost coincident with those of p-doping level between 10^<18> and 5x10^<18> cm^<-3>. These results show that the wafers will be used for lasers with carrier injection level of 10^<18> cm^<-3> or more.
(5) Disordering of superlattices : Wafers with (24 AlAs/GaAs DBR) / (p-GaAs conducting layr) / (GaAs/InGaAs/GaAs strained double quantum wells) / (n conducting GaAs layr) / (5-10 AlAs/GaAs DBR), for micro laser structure are grown by the MBE with a computer controlled system successfully. Si bas been diffused under As pressure at 850C for 20 hr in an evaquated quartz tube, which followed by Zn diffusion at 600C for 4 hr using SiN films for diffusion masks. Both Si and Zn disordering have been observed by SEM,which are conirmed to be applied for fabrication of planar micro surface emitting laser with low threshold. Less
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Research Products
(2 results)
