摘要:

We investigated the thermally induced redistribution of Rh in low pressure MOCVD grown InP structures by means of secondary‐ion‐mass‐spectroscopy. Analogous measurements for InP:Fe structures serve as reference. On alternately Rh‐doped/undoped InP structures an upper limit for the diffusion coefficient ofDRh(800 °C)≤1×10−14cm2/s is established much smaller thanDFe(750 °C)=1×10−11cm2/s. No exchange reactions are observed at the interface ofp‐InP/InP:Rh structures. Only Rh implanted into InP shows defect induced redistribution into amorphous areas. Rh is superior to Fe as far as thermal stability is concerned. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114542

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

For implanted phosphorus in the dose range of 5×1013/cm2–4×1014/cm2, up to half the implanted dose may be lost during low thermal budget anneals due to transient diffusion and anomalous segregation at the Si–SiO2interface. The phosphorus atoms, rendered mobile by the implant damage, stick in the oxide near the interface where they are electrically inactive and can be removed by stripping the surface oxide. Such a dose loss needs to be accounted for in a typical device fabrication process. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114543

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Diamond crystals of 1 &mgr;m mean size were grown on (100) silicon substrates by ArF (193 nm) laser ablation of graphite in a hydrogen atmosphere with a laser power density of 1.3×108W/cm2at relatively low substrate temperature (450 °C). Raman spectroscopy analysis confirmed the diamond cubic structure of the crystals by the presence of a sharp peak at 1332 cm−1. When a KrF (248 nm) laser was used instead of the ArF no diamond phases were detected in the deposited films and the Raman spectra showed only the two bands centered at 1340 and 1600 cm−1characteristic of amorphous carbon. The results demonstrated that the laser wavelength is a determinant parameter in the growth of diamond by laser ablation of graphite. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114544

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Material transformations occurring at the facets of optically ‘‘stressed’’ planar InGaAsP/InP diode lasers have been investigated by transmission electron microscopy and energy dispersive x‐ray spectroscopy. Catastrophic degradation lines (CDLs) which are characteristic of catastrophic optical damage are observed for optical power densities ∼107W/cm2. Analysis of the microstructure reveals a series of 150 nm wide GaAs‐rich tracks and the formation of unique void/InGa‐rich precipitate pairs within the InGaAsP active layer. These observations suggest that the formation of local group III‐rich regions is the first stage in the formation of CDLs. Subsequently, the strong absorption of the impinging laser beam leads to propagation of an InGa‐rich melt, thereby producing the GaAs‐rich tracks through a process similar to liquid phase epitaxy. These results are discussed in the context of standard physical models for CDLs. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114545

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Fourier transform infrared spectrometry, visual transmission spectroscopy, andinsituellipsometry have been performed on plasma beam deposited (PBD) amorphous hydrogenated silicon layers. From these measurements refractive index at infrared wavelengths and at 632.8 nm, the optical band gap and the hydrogen content of the layers have been determined. The hydrogen concentration of the layers varies between ∼9 and 25 at. %. It was found that the refractive index decreases more with hydrogen concentration in the layer than predicted by theoretical calculations assuming tetrahedral structures. The band gap of the material remains constant at ∼1.72 eV for the range of hydrogen contents measured. The resonance frequency of the SiH stretching mode (around 2000 cm−1) increases with increased hydrogen content. This is additional evidence to support the assumption that clustered SiH (SiH on voids) does not have its stretching mode near the 2100 cm−1SiH2peak. From the results presented it is concluded that PBD layers show behavior similar to plasma enhanced chemical vapor deposition layers with respect to the hydrogen content in the layers. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114546

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A silicon surface tunneling transistor structure, based on lateral band‐to‐band tunneling, is presented. The theory, fabrication, and operation of the device is described. Band‐to‐band tunneling is controlled by the bias on the gate of the device which modulates the width of the tunneling barrier. The operation of the device is confirmed in both experimental results and two‐dimensional computer simulations. Dramatic differences in drain current are observed for different gate bias. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114547

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Spatially resolved values of the Al‐Ga interdiffusion coefficient forp‐i‐nandn‐i‐pAlGaAs‐GaAs device structures are found to be nearly identical in magnitude, but to vary with position by a factor of 2 across a 1 &mgr;m thick multiple quantum well active region. These observations are in marked contrast with theoretical predictions given that the Fermi level to valence‐band energy separation changes by 0.7 eV across the intrinsic region and suggest that impurity‐free layer disordering does not provide the necessary uniformity in energy shift for photonic integrated circuit fabrication in its present state of development. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114548

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Thermal oxidation of (100) and (111) silicon (Si) in a nitrous oxide (N2O) ambient has been studied. The oxidation rate follows a parabolic to linear behavior. The activation energies in the parabolic regime were found to be 2.02 and 1.54 eV/molecule for (100) and (111) Si, respectively. The activation energy for the linear rate constant is estimated to be 1.61 and 1.37 eV/molecule for (100) and (111) Si, respectively. The limiting mechanism for the parabolic regime is attributed to the diffusion of oxidant through a surface oxynitride layer. The gradual shift to linear behavior is unusual and is in direct contrast with the Grove–Deal model [J. Appl. Phys.36, 3770 (1965)]. Finally, secondary ion mass spectrometry shows a temperature dependent distribution and concentration of nitrogen at the interface. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114549

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report the observation of the quantum‐confined Stark effect (QCSE) in the photoluminescence (PL) of ZnSe/ZnCdSe single quantum wells grown by molecular beam epitaxy. The electric field was applied via a reverse‐biased Schottky barrier contact. Red shifts of the PL peak as large as 13 meV were detected, and accompanied by a dramatic reduction in the transition intensity, consistent with the QCSE. Even moderate applied voltages (∼5 V) were sufficient to completely quench the luminescence signal. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114550

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We have fabricatedp‐type PtSi/SiGe/Si Schottky diodes with barrier heights (from photoresponse) that are lowered (relative to PtSi/Si) and highly dependent on the applied bias. The variability in the barrier height is obtained by using the SiGe/Si valence band offset as an additional barrier. When placed in close proximity to the PtSi/SiGe Schottky barrier, the total effective barrier can be altered dramatically by adjusting the applied reverse bias. The voltage sensitivity of the total barrier height can be controlled by the SiGe layer thickness. The voltage‐variable barrier heights range, for example, from 0.30 eV at zero bias to 0.12 eV at 2.4 V reverse bias for a 20%, 450 A˚ thick SiGe layer. This lowest barrier height corresponds to a cutoff wavelength of 10 &mgr;m, extending the detection range of PtSi infrared detectors to the long‐wavelength range. The quantum efficiency coefficientsC1are normal at this long‐wavelength end, but reduced over the rest of the tunable range, because hot carriers have to traverse the entire SiGe thickness in order to be detected. The hot carriers’ energy losses from quasielastic scattering in the SiGe are taken into account in a theoretical model that gives good agreement with data. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114551

出版商:AIP    

年代:1995

数据来源: AIP