摘要:

TiNxdiffusion barriers have been deposited onton‐Si wafers by reactive sputtering in a N2+Ar atmosphere, with a nitrogen content varying in the 0%–25% range. The relative composition of the as‐deposited films was examined by Rutherford backscattering spectroscopy (RBS) and Auger electron spectroscopy (AES) analysis yielding a TiNxcomposition betweenx=0.8 andx=1.2, respectively. The near stoichiometric samples were thermally annealed at temperatures between 600 and 900 °C in vacuum and N2atmosphere. Films with composition TiN1.1and TiN0.9present very good behavior as barrier layers against the Si diffusion and a very low reactivity with the Si substrate. When the nitrogen content in the as‐deposited films decreases, the films lose their barrier properties. For the TiN0.8samples, Si diffusion through the films is observed after annealing in vacuum at temperatures of 600 °C and above. However, when the heat treatment is carried out in a N2atmosphere an improvement in the barrier characteristics and reactivity with the Si at the interface was observed.

ISSN:0734-211X    

DOI:10.1116/1.585455

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The reaction of amorphous Co–Zr films with Si(100) and SiO2substrates has been investigated usinginsituRutherford backscattering spectrometry, Auger electron spectroscopy and x‐ray diffraction. For this purpose, CoxZr1−x(x=0.5 or 0.6) films were deposited on a substrate and annealed in vacuum or NH3. During annealing of an amorphous Co–Zr film on Si in vacuum at a temperature lower than 600 °C, Co reacts with Si, forming CoSi2next to the substrate. Above 600 °C, the layer reacts completely with Si and the following structure develops: (ZrSi2+CoSi2)/CoSi2/Si. Annealing the same structure in NH3above 600 °C causes two reactions to occur simultaneously: (i) CoSi2formation at the film/substrate interface, and (ii) nitridation of the film surface, forming ZrN, which stops the diffusion of Si to the surface. It was found that a fraction of the CoSi2grains was aligned with the Si(100) substrate, irrespective of the annealing ambient. This fraction increases with increasing annealing temperature. When annealing below 600 °C in NH3, an oxide layer between the surface nitride layer and the interface silicide layer develops, retarding the formation of the nitride and silicide layer. On SiO2the situation is complex since Zr reacts with SiO2above 600 °C, resulting in a ZrO2toplayer with underneath a Co–Si layer after annealing in vacuum. In NH3an oxygen‐containing layer between the substrate and the ZrN top layer is formed.

ISSN:0734-211X    

DOI:10.1116/1.585457

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The crystalline quality of Ge grown epitaxially on Si can be improved by using GeH4/H2gas low‐pressure chemical vapor deposition at a low temperature of 410 °C and surface‐cleaning processing with a purified‐H2flow prior to GeH4introduction into a CVD reactor. H2flow processing is carried out at growth temperature. The dislocation density of a 1.3‐μm thick Ge film is nearly 2×108cm−2, which is as low as that of molecular‐beam epitaxy (MBE)‐grown Ge films. Stacking faults commonly generated in the CVD‐grown Ge films at temperatures higher than 700 °C are not observed. The 700 °C heat treatment of the Ge film reduces dislocation density to 2×107cm−2and causes no interface reaction between Ge and Si. This technique is superior to conventional chemical vapor deposition (CVD) techniques for Ge epitaxial growth.

ISSN:0734-211X    

DOI:10.1116/1.585458

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The fully relaxed Si/Ge heteroepitaxial films are simulated via molecular dynamics with Tersoff’s potential for Si–Si, Si–Ge, and Ge–Ge interactions. The lattice mismatch induced strain is computed as a function of the thickness of the film. The strain values of the bulk Si and Ge layers are found to be in excellent agreement with those obtained viaabinitiolocal density functional calculations. In thick uncapped epitaxial films, we find that the surface reconstruction induced relaxations significantly alter the strain values in the top five layers. When the film is less than five layers thick, we show for the first time that these relaxations do not cross the Si/Ge interface but are fully contained within the epitaxial film region. For all of the geometries studied, it has been found that at the Si/Ge interface, the adjacent Ge layer moves towards the interface and the adjacent Si layer moves away from the interface. Though very small in magnitude, these additional relaxations significantly alter the generally assumed geometries of the Si2Ge2/Si{001}, Si4Ge4/Si{001}, Si3Ge1/Si{001}, and Si1Ge3/Si{001} superlattices.

ISSN:0734-211X    

DOI:10.1116/1.585459

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We present a method to calibrate the profile of Al mole fraction versus depth, deposited in growth of graded AlxGa1−xAs alloys in a molecular‐beam epitaxy machine. A computer is used to either ramp the Al oven temperature (analog alloy), or pulse the Al beam (digital alloy), with a fractional monolayer depth resolution that permits averaged alloy profiles corresponding to a range of different design profiles to be obtained. The profiles are measured in calibration runs by using a fast picoammeter to track the ion‐collector current of the beam flux monitor ion gauge (facing the ovens), and integrating the ion current with time. Parabolic quantum wells are grown by either technique and the corresponding measured profiles are compared to each other and to the design profile. The ability of the digital‐alloy technique to obtain almost arbitrarily varying graded‐alloy profiles is illustrated.

ISSN:0734-211X    

DOI:10.1116/1.585460

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The surface topography and the chemical composition of anodic oxides on GaP have been studied. The surface of the as grown anodic oxide was featureless but annealing atT≥600 °C causes the formation of hollow bumps and blisters which increase in size with temperature or duration of the anneal. The oxide composition was investigated by x‐ray photoelectron spectroscopy (XPS) and was found to be a nonuniform mixture of P2O5, Ga2O3, and GaPO4. There is some evaporation of phosphorus oxide near the surface when annealed atT≥300 °C but little or none from the bulk of the oxide film.

ISSN:0734-211X    

DOI:10.1116/1.585461

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The adsorption and desorption of sulfur on a GaAs (001) surface was studied usinginsituAuger electron spectroscopy and reflection high‐energy electron diffraction (RHEED). The H2S ‐treated surface showed a (2×1) sulfur‐terminated structure, with the sulfur considered to be a few monolayers thick. RHEED patterns showed that the (2×1) reconstruction changed into an arsenic‐stabilized (2×4) structure when heated to 590 °C under an arsenic flux. A sulfur Auger signal on the H2S ‐treated surface was found to completely dissapear upon heating. These data show that H2S exposure is appropriate for preparing a sulfur‐terminated surface and that high‐quality crystal regrowth is possible on the surface after being heat treated.

ISSN:0734-211X    

DOI:10.1116/1.585418

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The adhesion between a silicon nitride layer and polycarbonate substrate was improved by employing a silicon interfacial layer which was deposited by a microwave plasma enhanced chemical vapor deposition technique. The silicon interfacial layer had an interpenetrating layer composed of the two materials, which provided an anchoring effect. In the interpenetrating layer, it was assumed that chemical bonding between carbon of the polycarbonate substrate and the silicon interfacial layer occurred through the oxygen when the radio frequency power was used in the fabrication process. The oxygen originated in the polycarbonate substrate. During the silicon interfacial layer deposition, carbon was sputtered and oxygen reacted with silicon.

ISSN:0734-211X    

DOI:10.1116/1.585419

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

A very efficient method is described for the simulation of the resist development process in electron beam lithography. This method is based on Fermat’s principle of geometric optics, and the derived systems of differential equations are solved as boundary value problems. By way of this new idea, a compact representation of the computed results is obtained, the difficulties with the ‘‘loops’’ are avoided, and an efficient mathematical algorithm leads to a very small calculation time. This approach is applicable to optical lithography also. The results of typical examples are presented and briefly discussed.

ISSN:0734-211X    

DOI:10.1116/1.585420

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Scanning tunneling microscopy is used to provide integrated imaging, processing and electrical characterization on the nanoscale level for the same defect region in CuInSe2. The use of coordinated electronic and photon biasing is demonstrated to provide specific atomic imaging for covalently bonded semiconductors. The high‐resolution conditions of the instrument provide for nanoprocessing with passivation of defects using oxygen. The same regions are analyzed for minority‐carrier losses by a nanoscale electron‐beam induced current technique.

ISSN:0734-211X    

DOI:10.1116/1.585421

出版商:American Vacuum Society    

年代:1991

数据来源: AIP