摘要:

Substitutional carbon in Czochralski Si is found to decrease the formation rate for a 935 cm−1infrared absorption band under neutron irradiation while that for a 965 cm−1band (interstitial carbon trapped at interstitial oxygen) increases. The observations support a controversial previous assignment of the 935 cm−1band to a center with interstitial Si trapped by interstitial oxygen.

ISSN:0003-6951    

DOI:10.1063/1.101625

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report on the first direct evidence of a gettering effect induced by rapid thermal processing (RTP). Homogeneously gold‐doped silicon is studied before and after RTP by deep level transient spectroscopy measurements of the Au acceptor level. After a 1000 °C/10 s cycle, gold is depleted in three regions below the surfaces, indicating a gettering effect. The mechanism for this RTP‐induced gettering is discussed.

ISSN:0003-6951    

DOI:10.1063/1.101626

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Zn diffusions from spin‐on films have been carried out inton‐InP/p+‐InGaAs/n‐InP heterostructures, which were grown by metalorganic vapor phase epitaxy for heterojunction bipolar transistors with Mg as apdopant. After diffusion, Mg was completely substituted by Zn and enriched in the spin‐on film. In the presence of Mg, the indiffusion of Zn is strongly enhanced. By varying doping levels and diffusion conditions, the underlying mechanism is studied and compared to recent experiments with Be‐doped AlGaAs/GaAs heterostructures.

ISSN:0003-6951    

DOI:10.1063/1.101627

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Heavily dopedp+andn+silicon epitaxial layers were continuously grown at 600 °C using photoenhanced epitaxy. The heavily phosphorus‐doped photoepitaxial layer with a carrier concentration above 1×1017cm−3grown on thep−substrate shows very high density surface pits due to phosphorus precipitation, suggesting poor crystal quality. Unexpectedly, when thisn+photoepitaxial layer is continuously grown on a heavily boron‐dopedp+photoepitaxial layer at a boron concentration above 1×1019cm−3, surface pits completely disappear and crystal quality is greatly improved. The very low growth temperature enabled an extremely abrupt impurity profile to be achieved for thep+‐n+layer.

ISSN:0003-6951    

DOI:10.1063/1.101628

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The finite element method was used for calculating the wave functions and energy levels of electrons in arbitrarily shaped two‐dimensional quantum‐confined structures. The calculated results indicate the possibility of quasi‐quantum wires by simply growing single quantum wells on corrugated substrates.

ISSN:0003-6951    

DOI:10.1063/1.102258

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Tunneling of electrons between double quantum wells is investigated by time‐resolved photoluminescence in the picosecond regime. The samples contain two In0.53Ga0.47As quantum wells with different widths, separated by various InP barriers. At low excitation density, the luminescence decay time of the narrower quantum well depends strongly on the thickness of the barrier, revealing the lifetimes to be tunneling controlled. A semiclassical model explains the observed nonresonant tunneling escape times. With increasing density, the luminescence decay time of the narrower quantum well strongly increases and finally saturates due to effective mass filtering, which leads to a lineup of the electron levels in both wells and resonant tunneling.

ISSN:0003-6951    

DOI:10.1063/1.101615

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Excitonic and band‐to‐band absorption spectra are calculated for vertical incident radiation for the InAs/AlGaSb multiple quantum well structures. Due to the special band lineup of this heterostructure, the absorption spectra can be tailored to respond in far infrared. The electric field dependence of the spectra shows blue shift and enhanced absorption in contrast to the situation in type I quantum wells. Applications to far infrared detectors are discussed.

ISSN:0003-6951    

DOI:10.1063/1.101616

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Optical transitions between quantum well subbands have large oscillator strengths and narrow linewidths so that they can be used for the detection of infrared light. Here we show that the intersubband separation can be varied over a wide energy range by depositing a thin barrier layer of AlGaAs in the middle of a GaAs well. In a sufficiently narrow well it should be possible to push the subbands out of the well, i.e., perform the transition from the quasi‐two‐dimensional case to the quasi‐three‐dimensional case.

ISSN:0003-6951    

DOI:10.1063/1.101617

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A metal‐insulator‐semiconductor field‐effect transistor (MISFET) using the InAs‐GaAs superlattice as a channel layer has been successfully demonstrated for the first time. Device structure was grown by molecular beam epitaxy. The MISFET with 1.0 &mgr;m gate length exhibits a maximum external dc transconductance of 212 mS/mm atVds=3.0 V andVg=−1.5 V. This value is high among 1.0 &mgr;m gate length devices.

ISSN:0003-6951    

DOI:10.1063/1.101618

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A unique method of patterning YBaCuO thin films based on the inhibition of superconductivity by Si‐YBaCuO intermixing has been developed. In the experiment, a thin Si film was first evaporated on a MgO substrate and subsequently patterned using laser direct‐write etching. Multilayered YBaCuO thin films were then deposited bye‐beam evaporation and annealed in a rapid thermal annealing system for 30–90 s at 980 °C. The YBaCuO film deposited on the silicon regions became insulating. Auger depth profiling measurements indicate that Si‐YBaCuO intermixing had occurred in these areas. Between the insulating regions, narrow YBaCuO superconducting lines were formed. For both 10‐&mgr;m‐wide, 1‐mm‐long and 2.5‐&mgr;m‐wide, 80‐&mgr;m‐long lines, theTcwas observed above 76 K. The critical current density of the lines was measured to be 300 A/cm2at 75 K. This patterning technique may be useful for fabrication of highTcsuperconducting interconnects and devices.

ISSN:0003-6951    

DOI:10.1063/1.102448

出版商:AIP    

年代:1989

数据来源: AIP