Kent W. Carey

Room-temperature continuous-wave operation of 1.54-μm vertical-cavity lasers

We report on the room-temperature continuous-wave operation of vertical-cavity lasers operating at 1.54 /spl mu/m. The devices use a 7 strain-compensated quantum-well active layer sandwiched between two Al(Ga)As-GaAs quarter-wave mirrors joined by wafer fusion. Five device sizes between 8 and 20 /spl mu/m were found to operate continuously at room temperature (23/spl deg/C), The lowest room-temperature continuous-wave threshold current of 2.3 mA was measured on an 8-/spl mu/m diameter device, while the highest continuous-wave operating temperature of 33/spl deg/C was measured on a 12-/spl mu/m device.<<ETX>>

GAAS TO INP WAFER FUSION

This paper presents an analysis of the various properties of the fused interface between GaAs and InP. Interface dislocations are characterized by transmission electron microscopy. Bipolar electrical properties are studied by electron beam induced current measurements and by electrical measurements of fused diode and laser structures. Absorptive optical losses at the interface are estimated from measurements on fused Fabry–Perot resonators and optical scattering losses from interface roughness are estimated by atomic force microscopy. Finally a preliminary mechanical analysis of fracture patterns of fused mesas is presented. The results from our analysis are used to develop guidelines for the fabrication of fused optoelectronic devices.

High‐precision band‐gap determination of Al0.48In0.52As with optical and structural methods

The band gap of Al0.48In0.52As lattice matched to InP is determined with high precision at 1.5 and 300 K as 1.511 and 1.439 eV, respectively. This determination, which resolves a long lasting dispute on the most fundamental material parameter of this semiconductor, is based on a comparative study of temperature‐dependent photoluminescence, wavelength‐dispersive x‐ray analysis, and triple‐crystal x‐ray diffractometry.

Composition non-uniformities in selective area growth of GaInAs on InP grown by OMVPE

Selective area epitaxial growth of Ga0.47In0.53As on InP substrates patterned with silicon nitride was done by low pressure organometallic vapor phase epitaxy. Good surface morphology and clean side walls of the epitaxial layers were obtained in most of the areas of selective GalnAs growth. However, both GaAs incorporation and InAs incorporation increased near the edges of the selective growth areas due to the extra flux of Gacontaining and In-containing species migrating on the surface of silicon nitride. The increase in InAs incorporation was found at a higher rate when the adjacent silicon nitride area was large, hence, cross-hatching appeared near the edges. A characteristic length of adjacent silicon nitride seemed to be connected with the enhanced InAs incorporation, which was about 40μm at 600°. The non-uniformities in composition appeared in all wafers grown in the temperature range between 570 and 650°.

Structural and photoluminescent properties of GaInAs quantum wells with InP barriers grown by organometallic vapor phase epitaxy

Ga0.47In.53As/InP quantum well structures grown by atmospheric pressure organometallic vapor phase epitaxy are characterized by high‐resolution transmission electron microscopy (HRTEM) and 4 K photoluminescence (PL). Microdensitometer analysis of the HRTEM images shows GaInAs wells as narrow as 10 A with slightly asymmetric interface widths. The InP to GaInAs transitions occur within 200 monolayers while the GaInAs to InP transitions are 3–5 monolayers wide, probably due to As carryover. 4 K PL shows half‐widths below 9 meV for quantization shifts up to 140 meV. PL peak shifts as large as 395 meV for the narrowest quantum wells are observed compared to bulk Ga0.47In0.53As.

Organometallic vapor phase epitaxial growth and characterization of high purity GaInAs on InP

GaInAs grown on InP at atmospheric pressure using organometallic vapor phase epitaxy is characterized by x‐ray diffraction, transmission electron microscopy (TEM), and Hall measurements. The sources used are TMIn, TMGa, AsH3, and PH3 in a carrier gas of H2. Double crystal x‐ray diffraction is used to evaluate the mismatch and crystal quality of the GaInAs epitaxial films. Full widths at half‐maximum intensity (ω1/2) of the double crystal diffraction peak as small as 50 arc s are obtained. The average ω1/2 is less than 80 arc s for all films grown at deposition temperatures between 520 and 540 °C and with mismatch strains between −4×10−3 and +1×10−3. Standard TEM is used to image Ga0.47In0.53As on InP in cross section. No planar defects and few dislocations are present. High resolution TEM of the Ga0.47Ino.53As/InP interface shows that no strain or mismatch related defects are present for nearly lattice‐matched films. Hall mobilities of 10 500 and 47 500 cm2/Vs at 300 and 77 K are measured at n=2×1015 cm−3. These values are comparable to those of good liquid phase epitaxial layers.GaInAs grown on InP at atmospheric pressure using organometallic vapor phase epitaxy is characterized by x‐ray diffraction, transmission electron microscopy (TEM), and Hall measurements. The sources used are TMIn, TMGa, AsH3, and PH3 in a carrier gas of H2. Double crystal x‐ray diffraction is used to evaluate the mismatch and crystal quality of the GaInAs epitaxial films. Full widths at half‐maximum intensity (ω1/2) of the double crystal diffraction peak as small as 50 arc s are obtained. The average ω1/2 is less than 80 arc s for all films grown at deposition temperatures between 520 and 540 °C and with mismatch strains between −4×10−3 and +1×10−3. Standard TEM is used to image Ga0.47In0.53As on InP in cross section. No planar defects and few dislocations are present. High resolution TEM of the Ga0.47Ino.53As/InP interface shows that no strain or mismatch related defects are present for nearly lattice‐matched films. Hall mobilities of 10 500 and 47 500 cm2/Vs at 300 and 77 K are measured at n=2×1015 cm−3...

A novel three‐step process for low‐defect‐density silicon on sapphire

A novel three‐step process for producing low‐defect‐density epitaxial silicon layers on sapphire substrates has been developed. The three‐step process utilizes a simple room‐temperature ion implantation and solid‐phase epitaxial regrowth. Both megaelectron volt helium backscattering and transmission electron microscopy (TEM) results indicate the excellent crystalline quality of silicon‐on‐sapphire (SOS) wafers produced by the three‐step process. The backscattering minimum yields at the interface and the surface of the three‐step SOS layer are 0.14 and 0.03, respectively. A TEM micrograph of the top 500 A of the three‐step SOS layer shows none of the planar defects which are common to standard SOS layers.

Characterization of InP/GaInAs/InP heterostructures grown by organometallic vapor phase epitaxy for high-speed p-i-n photodiodes

Organometallic vapor phase epitaxy at atmospheric pressure is used to grow InP/Ga0.47In0.53As/InP p-i-n photodiode structures designed for high speed operation. Growth of high purity Ga0.47In0.53As and abrupt InP/GaInAs heterointerfaces is combined to make the fastest reported front-side illuminated GaInAs p-i-n detectors. High resolution transmission electron microscopy (HRTEM) examination of the InP/GaInAs interfaces indicates that the transitions are abrupt to about 4 monolayers or less. No misfit dislocations are detected at the InP substrate/GaInAs epitaxial layer interface or the GaInAs/InP epitaxial interface. The purity of n−-GaInAs is evaluated using photoluminescence at 1.5 K and Hall measurements at 77 K. The full width at half maximum (FWHM) of the GaInAs photoluminescence is 1.5 MeV at 1.4 K, the best value reported to date. The Hall mobility is as high as 64,000 cm2/V·s for n = 5×1014cm−3 at 77K. The lowest dark current measured is 0.15 nA at −4 V for a 50 μ m diameter photodiode with a 25 γm bonding pad or 6×10−6 A/cm2. This is among the best values reported to date. The bandwidth of a packaged photodiode with a 25 γm diameter photosensitive region is 17–20 GHz.

Low-defect-density silicon on sapphire

Abstract Low-defect-density epitaxial silicon films on sapphire substrates have been produced using a novel three-step process. This three-step process is a hybrid of vapor-phase epitaxial growth and solid-phase epitaxial regrowth. The solid-phase regrowth is preceded by a simple room temperature Si ion implantation. X-ray rocking curves, MeV helium backscattering and transmission electron microscopy (TEM) are used to evaluate the crystalline quality of silicon-on-sapphire (SOS) wafers produced by this method. The full-width-at-half-maximum intensity of the X-ray rocking curve of this material is typically less than 600 arc seconds for a 600 nm layer. The best backscattering minimum yields at the interface and the surface of the three-step SOS layer are 0.12 and 0.03, respectively. These values indicate that the crystalline quality is much superior to that of normal SOS films prepared by chemical vapor deposition (CVD). Cross-sectional TEM micrographs indicate reductions in both the dislocation and microtwin densities.

Wafer Fusion for Surface-Normal Optoelectronic Device Applications

This paper discusses the issues connected with the application of fusion bonding technology for surface-normal optoelectronic devices (III-V semiconductors). The InP/GaAs fusion bonding technology employed in the development of long-wavelength vertical-cavity lasers is described.