摘要:

InGaAs epitaxial layers have been doped with beryllium with concentrations ranging from 1016to 5×1019cm−3as measured by secondary ion mass spectroscopy (SIMS). From electrical measurements we have observed thatp‐type layers presented a high degree of compensation, and for a doping level below 5×10−7cm−3, they are often found to bentype. SIMS analysis shows that oxygen is responsible for such behavior. Beryllium doping leads to incorporation of a large amount of oxygen in the epitaxial layers. Investigations on the origin of oxygen incorporation show that it is extremely sensitive to the residual vacuum during the growth and can be reduced by decreasing arsenic pressure.

ISSN:0003-6951    

DOI:10.1063/1.98566

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

It was found experimentally that polarizable capacitance versus voltage (C‐V) characteristics for metal‐oxide‐silicon (MOS) capacitors, passivated by various oxide glasses, depend on molar polarizability for passivation glasses. Experimental data showedC‐Vcurve shifts toward higher voltage were evidently caused by polarizable ions in glasses. The possibility for making a material choice in semiconductor device passivation was discussed, using the Poisson equation for the glass‐passivated MOS capacitors.

ISSN:0003-6951    

DOI:10.1063/1.98567

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The conduction types of ZnSe‐ZnTe strained‐layer superlattices (SLS’s) have been controlled by using the modulation doping technique. Two kinds of modulation‐doped SLS’s were prepared. One of them consisted of gallium (Ga) doped ZnSe layers and undoped ZnTe layers. The other consisted of undoped ZnSe layers and antimony (Sb) doped ZnTe layers. The conduction types of the samples modulation doped with Ga and Sb were shown to benandptype, respectively whereas the undoped samples exhibitedn‐type conduction. The electrical properties of the undoped and modulation‐doped samples were evaluated by the van der Pauw method. The carrier concentrations of all types of samples were about 5×1013/cm3at room temperature. The temperature dependence of the electrical properties was measured for an undoped sample and a sample modulation doped with Sb. The carrier concentrations increased with temperature and reached about 1×1017/cm3at 500 K.

ISSN:0003-6951    

DOI:10.1063/1.98568

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have studied photoluminescence of direct‐gap and ‘‘indirect‐gap’’ GaAs‐AlAs superlattices under electric field perpendicular to the layers. In the former case, the quantum confined Stark effect is observed as expected. In the latter case, reverse effects are found, providing evidence thatX‐like electron states are confined in the AlAs slabs.

ISSN:0003-6951    

DOI:10.1063/1.98569

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

In GaAs‐GaAsP strained‐layer superlattices grown lattice matched to GaAs are effective buffer layers in reducing dislocations in epitaxial GaAs films grown on Si substrates. The strained‐layer superlattice structure permits high values of strain to be employed without the strained‐layer superlattice generating dislocations of its own. We find that the strained‐layer superlattice buffer is extremely effective in blocking threading dislocations of low density and is less effective when the dislocation is high. It appears that for a given strained‐layer superlattice there is a finite capacity for blocking dislocations. Transmission electron microscopy has been used to investigate the role of the superlattice buffer layer.

ISSN:0003-6951    

DOI:10.1063/1.98570

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We undertake a reevaluation of the surface‐photovoltage diffusion‐length experiment, numerically solving the governing equations without any prior assumptions. We find that, although the technique is applicable for crystalline semiconductors, it does not measure, in general, a simple diffusion lengthLD=(kT&mgr;&tgr;)1/2for amorphous materials. It is demonstrated that this failure is attributable to the localized gap states inherent in amorphous semiconductors. The presence of localized gap states results in drift and diffusion terms of comparable magnitude and, hence, results in the inability to simply measure the (&mgr;&tgr;)1/2product. We also demonstrate that using thicker samples does not, in general, alleviate this problem.

ISSN:0003-6951    

DOI:10.1063/1.98571

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

By placing a semi‐insulating GaAs wafer on a flat, rare‐earth magnet, and irradiating the surface with two perpendicular slits of light to form a Greek cross configuration, it is possible to perform photoresistivity and photo‐Hall‐effect topography on the wafer. The technique is nondestructive in that the contacts are tiny, removable In dots which are placed only on the periphery. By varying the wavelength of the light, selective centers, such as EL2, can be mapped. We compare a 1.1‐&mgr;m, photoexcited electron concentration map with a quantitative EL2 map on a 3‐in. undoped, liquid‐encapsulated Czochralski wafer.

ISSN:0003-6951    

DOI:10.1063/1.98572

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Fundamental processes such as charge generation, trapping and emission, and collection in scanning deep level transient spectroscopy (SDLTS) are analyzed. It is concluded that SDLTS is more sensitive to minority‐carrier traps than to majority‐carrier traps and that a two‐dimensional map of SDLTS peak signal magnitude, i.e., SDLTS image, of minority‐carrier traps does not necessarily show the trap concentration distribution. A practical equation for trap concentration is derived by utilizing an electron beam induced current. Concentration of a hole trap with an activation energy 0.45 eV in ann‐type as‐grown liquid encapsulated Czochralski GaAs is calculated to be 1×1016cm−3.

ISSN:0003-6951    

DOI:10.1063/1.98573

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have developed a novel, simple technique for fabrication of one‐dimensional GaAs wires by utilizing only a focused ion beam (FIB) technology. The FIB implantation forms high‐resistive regions which confine ann+channel into a very narrow conductive wire. The minimum width of the GaAs wire fabricated by the present technology is 20 nm. Magnetoconductance of the wires shows a behavior of one‐dimensional localization and a conductance fluctuation due to a quantum interference effect. This is the first observation of the quantum interference effect in GaAs wires fabricated only by FIB implantation. Measured magnetoconductances are compared with the existing theories.

ISSN:0003-6951    

DOI:10.1063/1.98574

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The hydrogenation mechanism has been studied in the hydrogen plasma annealing of a polycrystalline silicon (polysilicon). Hydrogen depth profile measurements reveal that hydrogen atoms are introduced into the polysilicon by diffusion in which the diffusion constant and the surface density of hydrogen atoms increase as the rf power rises. The density of dangling bonds measured by electron spin resonance (ESR) shows that hydrogen atoms passivate dangling bonds more effectively with a higher rf power. By using the polysilicon hydrogenated at various rf powers, thin‐film transistors (TFT’s) have been fabricated to investigate the effect of hydrogenation on the TFT field‐effect mobility. The results show that hydrogen plasma annealing with a rf power of 50 W increases the field‐effect mobility. However, a decrease of the field‐effect mobility, which is considered to be caused by plasma induced surface damage, is also observed when the rf power is higher than 50 W.

ISSN:0003-6951    

DOI:10.1063/1.98575

出版商:AIP    

年代:1987

数据来源: AIP