31. |
Room‐temperature annealing of Si implantation damage in InP |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2570-2572
U. G. Akano,
I. V. Mitchell,
F. R. Shepherd,
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摘要:
Spontaneous recovery at 295 K of Si implant damage in InP is reported. InP(Zn) and InP(S) wafers of (100) orientation have been implanted at room temperature with 600 keV Si+ions to doses ranging from 3.6×1011to 2×1014cm−2. Room‐temperature annealing of the resultant damage has been monitored by the Rutherford backscattering/channeling technique. For Si doses ≤4×1013cm−2, up to 70% of the initial damage (displaced atoms) annealed out over a period of ≊85 days. The degree of recovery was found to depend on the initial level of damage. Recovery is characterized by at least two time constantst1<5 days and a longert2≊100 days. Anneal rates observed between 295 and 375 K are consistent with an activation energy of 1.2 eV, suggesting that the migration of implant‐induced vacancies is associated with the reordering of the InP lattice.
ISSN:0003-6951
DOI:10.1063/1.105957
出版商:AIP
年代:1991
数据来源: AIP
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32. |
Vertically coupled InGaAsP/InP buried rib waveguide filter |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2573-2575
R. C. Alferness,
L. L. Buhl,
U. Koren,
B. I. Miller,
M. Young,
T. L. Koch,
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摘要:
We report the first demonstration of narrowband (<17 A˚ full width at half maximum) wavelength selective grating‐assisted coupling between vertically stacked buried rib InGaAsP/InP channel waveguides. These vertically coupled channel waveguides form the basis both of integrable filters essential to photonic circuits such as amplifier/filter and demultiplexer/detector circuits as well as a general approach to vertical integration of photonic circuits.
ISSN:0003-6951
DOI:10.1063/1.105958
出版商:AIP
年代:1991
数据来源: AIP
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33. |
Removing native oxide from Si(001) surfaces using photoexcited fluorine gas |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2576-2578
Takayuki Aoyama,
Tatsuya Yamazaki,
Takashi Ito,
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摘要:
This letter discusses the reaction between (001) oriented Si surfaces and photoexcited fluorine gas resulting in the removal of the native Si oxide. For an F2/Ar gas system, the bulk Si was etched in areas where the native Si oxide had been completely removed. However, by using an F2/H2gas system, only the native Si oxide was removed. We used this method to remove the native Si oxide in Si epitaxial growth. A high‐quality single‐crystal Si film surface was obtained up to a maximum temperature of 600 °C through this Si growth process. We also characterized the etching of a thermal oxide, silicon nitride, and silicon carbide.
ISSN:0003-6951
DOI:10.1063/1.105930
出版商:AIP
年代:1991
数据来源: AIP
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34. |
New deep level luminescence bands observed from both a SiGe alloy layer and Si/Ge superlattice structures |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2579-2581
V. Higgs,
E. C. Lightowlers,
G. F. A. van de Walle,
D. J. Gravesteijn,
E. A. Montie,
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摘要:
Photoluminescence measurements have been made on Si/Ge short period superlattice structures grown on a SiGe alloy buffer layer and on a similar SiGe alloy layer without a superlattice. Using an InSb detector with a low energy cutoff at ∼450 meV, the major luminescence features observed were two broad bands with maximum intensities at ∼530 and ∼720 meV. The luminescence intensity was found to vary with the superlattice composition but was substantially stronger for the SiGe alloy layer without a superlattice. We ascribe these luminescence features to defects in the SiGe alloy layers. This is supported by the observation that the introduction of deliberate copper contamination at 600 °C dramatically increases the photoluminescence signal.
ISSN:0003-6951
DOI:10.1063/1.105908
出版商:AIP
年代:1991
数据来源: AIP
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35. |
AlGaAs/GaAs heterojunction bipolar transistor with a two‐dimensional electron gas emitter |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2582-2584
Q. Wang,
Y. Wang,
K. F. Longenbach,
E. S. Yang,
W. I. Wang,
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摘要:
We report the operation of the first two‐dimensional electron gas (2‐DEG) emitter heterojunction bipolar transistor. This device, which was grown by molecular beam epitaxy, incorporates an undoped GaAs spacer between the emitter and base of a standard AlGaAs/GaAs single‐heterojunction bipolar transistor. The introduction of the spacer layer causes the formation of a 2‐DEG at the AlGaAs/GaAs interface. This 2‐DEG defines the emitter side of the junction and produces an emitter‐base characteristic similar to that of the collector GaAs homojunction. Using a 300 A˚ GaAs spacer, offset voltages as low as 30 mV have been attained. These devices also exhibit current gains greater than 10 at emitter current densities of 3 A/cm2and gains up to 400 in the high current density regime.
ISSN:0003-6951
DOI:10.1063/1.105909
出版商:AIP
年代:1991
数据来源: AIP
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36. |
First direct observation of voids in bulk, undoped, semi‐insulating GaAs |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2585-2587
G. M. Williams,
A. G. Cullis,
D. J. Stirland,
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摘要:
Defect selectiveA/Bchemical etching, low‐temperature scanning cathodoluminescence, and transmission electron microscopy have been used to study the microstructure of undoped, semi‐insulating liquid‐encapsulated Czochralski GaAs wafers. It is shown for the first time that a distribution of microvoids is present in the bulk material at a number density of at least 1010cm−3. These microvoids, which are present in the centers of the dislocation cell structures observed in the GaAs, may result from the post‐growth heat treatment of ingots which is used to improve the material homogeneity. A possible explanation for the formation of these microvoids is given.
ISSN:0003-6951
DOI:10.1063/1.105910
出版商:AIP
年代:1991
数据来源: AIP
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37. |
Si1−xGex/Si multiple quantum well infrared detector |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2588-2590
R. P. G. Karunasiri,
J. S. Park,
K. L. Wang,
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摘要:
A long‐wavelength infrared detector is demonstrated using Si1−xGex/Si multiple quantum wells for the first time. A broad peak in the photoresponse is observed near 9 &mgr;m with a full width at half maximum of about 80 meV which provides the response in the 6–12 &mgr;m range. The position of the peak in the photoresponse is in good agreement with that observed in the absorption measurement using a waveguide geometry. A peak responsivity of about 0.3 A/W and detectivity ofD*=1×109cm &sqrt;Hz/W at 77 K are achieved. This suggests the possibility of monolithic integration of Si1−xGex/Si multiple quantum well detectors with signal processing electronics for potential focal plane array applications.
ISSN:0003-6951
DOI:10.1063/1.105911
出版商:AIP
年代:1991
数据来源: AIP
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38. |
Anomalous Hall effect and the anomalous infrared absorption inn‐type bulk Hg0.8Cd0.2Te |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2591-2593
J. G. Tian,
C. P. Zhang,
G. Y. Zhang,
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摘要:
The anomalous Hall effects and the anomalous infrared absorption dependence on temperature have been observed inn‐type bulk Hg0.8Cd0.2Te in the temperature range between 5 and 300 K. The existence ofp‐type inclusions in ann‐type matrix is considered as the cause of the anomalies. IR spectrum measurement is suggested to be employed to investigate the anomalous effects in bulk HgCdTe crystal.
ISSN:0003-6951
DOI:10.1063/1.105912
出版商:AIP
年代:1991
数据来源: AIP
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39. |
Patterning of epitaxial YBa2Cu3Oxinsulator multilayers with a high‐temperature‐resistant lift‐off mask |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2594-2596
B. Roas,
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摘要:
A new process for patterning of YBa2Cu3Ox‐insulator multilayers is described, using a high‐temperature‐resistant CaO process mask, which can be evaporated directly onto previously patterned YBa2Cu3Oxlayers and removed after film deposition. A crossover contact of two 3 &mgr;m wide and 30 &mgr;m long YBa2Cu3Oxstriplines has been fabricated by laser deposition, using this patterning technique. The upper and the lower stripline of the crossover contact showTcvalues of ≊89 K and a critical current densityjc(77 K) of 2 and 4×106A/cm2, respectively. The contact between the upper and the lower stripline is superconducting below 87 K. At 100 K, the normal conducting contact resistivity is 5×10−8&OHgr; cm2, based on a contact area of 3×3 &mgr;m.
ISSN:0003-6951
DOI:10.1063/1.105913
出版商:AIP
年代:1991
数据来源: AIP
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40. |
Growth of (Pb0.75Cu0.25)Sr2(Y1−yCay)Cu2O7thin films by laser ablation |
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Applied Physics Letters,
Volume 59,
Issue 20,
1991,
Page 2597-2599
R. A Hughes,
Y. Lu,
T. Timusk,
J. S. Presto´n,
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摘要:
In this letter we investigate the effects of varying the values ofxandyin (Pb1−xCux)Sr2(Y1−yCay)Cu2O7films deposited by laser ablation. The films are growninsituon (100) LaAlO3at the relatively low substrate temperature of 620 °C. The films are highly oriented with thec‐axis perpendicular to the substrate and exhibit a surface morphology which is unique to the oxide superconductors. By substituting Ca for Y it is possible to systematically vary the superconducting transition temperature from 10 K to a maximum of 86 K. On the other hand, variations in the value ofxseem to suggest that the film’s copper concentration in the (PbCu) plane can only exist within the narrow range of approximatelyx=0.2–0.3 and any extra copper added to the target ends up in an impurity phase.
ISSN:0003-6951
DOI:10.1063/1.105914
出版商:AIP
年代:1991
数据来源: AIP
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