摘要:

Very highly efficient GaAs–AlGaAs GRIN–SCH lasers were grown on ann‐GaAs substrate as well as on a semi‐insulating GaAs substrate by MBE. The threshold current densityJthof the lasers was found to be minimum when the thickness of the GaAs quantum well active layer is 6 nm. The lowestJthof 260 A/cm2was achieved for the broad‐area Fabry–Perot laser (the Al composition of the cladding layerx=0.7, the cavity lengthL=400 μm). A ridge‐waveguide (5 μm wide stripe) GaAs–AlGaAs GRIN–SCH laser, which is monolithically integrated with GaAs MESFET’s on a semi‐insulating GaAs substrate, exhibited cw operation with a threshold current as low as 19 mA at room temperature.

ISSN:1071-1023    

DOI:10.1116/1.582799

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

We report a single‐period modulation‐doped Ga0.47In0.53As/Al0.48In0.52As photoconductive detector for long wavelength applications. This detector shows a high equivalent external quantum efficiency. Furthermore, we have also measured the receiver sensitivity of this detector. At 1 Gbits/s, 1.3 μm, and BER=10−9, the receiver sensitivity is −25 dBm. These results suggest that, through further developments, this detector should find applications in monolithic integrated photoreceivers.

ISSN:1071-1023    

DOI:10.1116/1.582800

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

A study of three different types of buffers for GaAs power MESFET’s has been performed. Materials characterization was carried out by photoluminescence, DLTS and Hall measurements, and, as a final test, microwave performance of FET devices made from these materials was determined. It has been found that superlattice buffered structures consisting of 100 periods of 270 Å Al0.45Ga0.55As/30 Å GaAs show improvement in material quality and microwave performance over those of GaAs buffered devices.

ISSN:1071-1023    

DOI:10.1116/1.582801

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

Molecular beam epitaxy (MBE) grown wafers were used to fabricate GaAs distributed IMPATT (DIMPATT) diodes. All devices were of double‐drift, flat‐profile type and an additional AlxGa1−xAs layer was included in the structure to facilitate selective etching. The operation of DIMPATT diodes differ from the operation of conventional IMPATT’s since the electromagnetic waves are guided entirely within the device. Thus, the control of thickness and doping uniformity of the grown layers becomes extremely important. Additionally, the control of growth‐related defects is critical since DIMPATT’s are inherently very large area devices. Details of MBE growth and device results are discussed.

ISSN:1071-1023    

DOI:10.1116/1.582802

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

GaAs millimeter‐wave IMPATT diode material has been grown by molecular beam epitaxy. The epitaxial structure contained the double‐drift Read doping profile. Silicon and beryllium were used as theN‐ andP‐type dopants, respectively. TheNandPspikes were 300 Å wide and separated by 800 Å of doped material. The substrate temperature was 590 °C and the growth rate was 1 μm/h. Although some Debye spreading is present in this thin‐layered structure, useful doping versus depth information was obtained by capacitance–voltage (C–V) profiling. From theC–Vmeasurements and secondary ion mass spectrometry measurements we did not observe any significant diffusion of the silicon and beryllium dopants with the above growth conditions. The maximum doping level of the spikes was 1×1018cm−3. The epitaxial material was fabricated into single‐mesa IMPATT diodes. Sharp reverse breakdown characteristics were obtained. The uniformity of the breakdown voltages over a 1 in. radius of the wafer was excellent. Initial rf measurements have been performed at 60 GHz. A cw power of 1.24 W with 11.4% efficiency was measured at 60.5 GHz. The diodes exhibit good ruggedness. Junction temperatures in excess of 250 °C have been obtained without burnout.

ISSN:1071-1023    

DOI:10.1116/1.582803

出版商:American Vacuum Society    

年代:1984

数据来源: AIP

摘要:

We report results of theoretical investigations to understand the atomistic mechanisms responsible for controlling the surface roughness and concentration of native point defects in MBE grown GaAs. We have simulated growth of GaAs using both As2and As as the sources of anions in the vapor phase using Monte Carlo techniques. In the case of As2as a source, we have examined several possible reaction pathways for the dissociative chemisorption of As2and their influence on the quality of the grown system (under anion overpressure). Different reaction pathways introduce different constraints for the incorporation of atoms from the vapors. These simulations indicate that lowering the constraints for As2chemisorption decreases the defect nucleation site concentration but leads to a rougher growth front profile. We also report results of studies on GaAs growth using monatomic As as a source. The mechanisms responsible for As and As2incorporation are expected to be very different and our model studies show important differences in the quality of the material grown. We have also examined the effect of varying the ratio of Ga to As vapor pressure on GaAs growth using monatomic As as a source and find that it has an important role in controlling the quality of the growth front profile.

ISSN:1071-1023    

DOI:10.1116/1.582804

出版商:American Vacuum Society    

年代:1984

数据来源: AIP