Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik Berlin (FBH). Jahresbericht 1995

Available from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Aufbau- und Verbindungstechniken fuer faser- und integriert-optische Sensoren (AVT-FIOS II). Teilvorhaben: Hochpraezises Fixieren von Fuegepartnern mittels Lasermikroschweissens Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(53,22) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Oberflaechenemittierende Halbleiterlaser mit vertikaler Resonatoranordnung. Oberflaechenemitterender Laser - Prozesstechnologie und Charakterisierung Abschlussbericht

In the last two years the main development of the VCSEL-structures aimed a minimum series resistance of the upper, p-doped mirror. In most of the proposed DBR-structures, with which some quite promising results were obtained, an AlGaAs layer was chosen for at least one of the #lambda#/4 layer pairs. In this project planar, vertical-cavity, surface-emitting lasers were developed, based on strained InGaAs/GaAs quantum wells with emission wavelength ranging from 900 to 1000 nm. These structures comprised binary (GaAs/AlAs) DBR-mirrors and were grown with MBE. The proton implanted, gain guided VCSEL-structure was preferred because of the good thermal characteristics and the single-mode laser emission. The epitaxy of the active region, Bragg mirrors and of the whole laser structure was optimized with the help of photoluminescence and spectral reflectance investigations. With the help of a global modelling concept, which simulates the thermal optical and electrical characteristics of a VCSEL, a new transition layer design was developed and led to impressive results (#rho#_m_i_n 1"*10"-"5#OMEGA#cm"2). Through the optimization of the implantation dose and energy (D = 4 x 10"1"4cm"-"2, E = 250 keV) and annealing parameters (T = 450 C, t = 150 s) resulting in a sufficient isolating resistivity (#rho# > 10"5#OMEGA#cm) and a low sheet and contact resistance (#rho#_5 #approx# 5 x 10"2#OMEGA#/#square#, #rho#_c #approx# 4 x 10"-"6#OMEGA#cm"2)VCSELs were realized demonstrating quite satisfactory laser parameters: I_t_h = 8 mA, V_t_h = 2.1 V,P_m_a_x = 2.3 mW (diameter 18#mu#m, on-wafer measurement, unbonded). These remarkably low threshold characteristics, as well as the high optical power fulfill all a piori conditions for future device use in system applications. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(22,48) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Hochleistungsdiodenlaser und diodengepumpte Festkoerperlaser. Laserphysikalische Grundlagen zur Strahlbildung, -formung und -fuehrung in III-V-Strukturen fuer hohe optische Leistungen. Grundsaetzliche Erforschung von Laserstrukturen hoher Leistung im Al-freien Materialsystem GaInAsP/GaAs mit Grundmodestrahlung im Wellenlaengenbereich 800-1000 nm Abschlussbericht

For the first time single-mode laser diodes having a RISAS-structure (Real Index Self Aligned Structure) and emitting at 940 nm were realized using epitaxial regrowth into channels etched into GaInP. These RISAS-lasers have low threshold current densities and show low internal losses and high internal efficiencies comparable to broad area devices realized in one growth step. Using optimized LOC-structures a half-width of the vertical farfield pattern of 20 -22 C is achieved. Due to the lower power density at the facets a COD-level of 1 W at 10 #mu#m aperture is obtained using an optimized facet coating procedure. At 800 nm emission wavelength laser diodes with Al-free quaternary quantum wells in AlGaAs/AlGaAs and GaInP/AlGaAs waveguide structures were studied. AlGaAs/AlGaAs waveguides reproducibly yield half widths of the vertical farfield pattern of 22 -25 C. Threshold current densities below 300 A/cm"2 and differential efficiencies of 75% at 100 #mu#m resonator length are obtained. Ridge waveguide lasers show a COD-level of 400 mW at 4 #mu#m width and an extrapolated lifetime exceeding 10000 h at 100 mW. The output power in the fundamental mode is around 150 mW. For diode lasers with GaInP waveguide layer the COD-level reaches 500 mW (4 #mu#m width) in Q-CW operation (1 ms pulses). Under CW operation COD did not occur due to thermal rollover at 400 mW. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(58,26) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Hochleistungsdiodenlaser und diodengepumpte Festkoerperlaser. Analyse und Aufbau von Material- und Schichtsystemen fuer Hochleistungsdiodenlaser. Prozessgrundlagen fuer Hochleistungsdiodenlaser im Materialsystem GaInAsP/GaAs Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(59,12) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Mikrosystembausteine fuer Hochtemperaturanwendungen. Hochtemperaturstabile Elektronik auf der Basis von GaAs Abschlussbericht

SIGLEAvailable from TIB Hannover: F96B1210+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Nichtkonventionelle ohmsche Kontaktsysteme fuer III-V-Halbleiter-Schichtsysteme Schlussbericht

Ohmic multilayer contact systems with diffusion barrier layers are investigated which should show improved long-time and/or temperature stability. The investigations concentrate on the system Au/Pt/Ti/ a-WSi_xN_y/Au/Ge/Ni-n-GaAs. Besides that the systems Au(Pt/Ti)/pc- or a-LaB_6/Au/Ge/Ni-, Au/Pt/Ti/WSiN/Ge/Pd-, Au/Pt/Ti/WSiN/InGaAs- on n-GaAs and Au/Pt/Ti/WSiN/Pt/Ti- on p-GaAs were treated. The layers were deposited in a combined electron beam evaporation/dc sputter equipment and the annealing treatments were performed in a RTA furnace. For the first-mentioned contacts the annealing parameters were optimized which yields contact resistances R_c of 0.1 #OMEGA#mm and specific contact resistances #rho#_c of some 10"-"7 #OMEGA#cm"2, respectively. After thermal stress of about 350 C/100 hours R_c is in the 0.3 #OMEGA#mm range. The contact system was applied as source/drain contacts in a MESFET process in order to demonstrate their usefulness. The behaviour of the alloying and of the (secondary-) phases after annealings could be studied by AES, SNMS, and XTEM/EDS/TED as well as XRD diagnostics. This type of ohmic contact proved to be useful for all III-V devices where flat (#<=#50 nm) contacts in the 0.1 #OMEGA#mm range are required. (orig.)Available from TIB Hannover: F96B17+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

GaInP-Leistungs-HBTs fuer Mobilkommunikation Abschlussbericht

SIGLEAvailable from TIB Hannover: F01B357+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Grundlegende Untersuchungen zur hochgenauen, beruehrungslosen laserinterferometrischen Messung grosser Laengen im Maschinenbau. Teilvorhaben: Grundlegende Untersuchungen leistungsstarker durchstimmbarer Halbleiterlaserdioden Schlussbericht

1. The basic physical and technological knowledge was worked out, to realise single frequency, tunable 1060 nm diode lasers. With an optimised epitaxial structure low threshold current densities below 100 A/cm"2 and high internal efficiencies near 100% were achieved. Gratings with very short periods of about 150 nm were formed by a holographic process and overgrown. A reproducible full 2''-wafer process was established to realise three contact DBR - diode lasers. Aging test showed a very good reliability over more than 1000 hours. 2. A reliable light source for a FMCW-laser radar was the goal of the investigations. The target was to measure a distance of several meters with a precision of 10 #mu#m... 100 #mu#m in a very short time <1s. 3. The design of the diode lasers was simulated. The epitaxial process for the first and second growth was studied. The processing of gratings and of fundamental mode diode lasers was investigated. Measurements for tuning characteristics and reliability were done. 4. A reproducible output power in single frequency regime of 150 mW was achieved. The frequency range covers 100 GHz for fast tuning (<1 ms) and 300 GHz in a slower run (around 10 ms). These results match the project goals very well and are higher than international results reported at this wavelength. Diode lasers were available for the project partners in time. 5. The results and the technological standing should be used for further supplying users in measurement and spectroscopic equipments. An other application concerns the using of these diode lasers as master oscillators in Nd:YAG-laser systems. The technological base should be used for other wavelength also. A very interesting task is the frequency doubling of such high power stable fundamental mode diode lasers, to get blue and green light directly from a diode laser for display technology, printing and so on. (orig.)SIGLEAvailable from TIB Hannover: F00B733+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Photonik II - Optische Kommunikationssysteme (Schluesselbauelemente). Teilvorhaben: Halbleiterpumplaser fuer 1,3-#mu#m-Faserverstaerker Schlussbericht

SIGLEAvailable from TIB Hannover: F01B1017+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman