摘要:

It is demonstrated that medium energy (10 keV) writing implantation of heavy ions into thin PMMA films produces photomasks which are locally opaque to UV and deep UV light. An excimer laser is an excellent illumination source for lithographic replication of these patterns because of its high UV light output and low spatial coherence. The writing beam implantation is performed on an electrostatic ion gun incorporating a liquid metal ion source (LMIS) of high brightness. Due to their similar spatial resolution limits, LMIS writing ion beam implantation and excimer laser illumination is an inherently compatible combination of mask production and mask replication techniques.

ISSN:1071-1023    

DOI:10.1116/1.583302

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Dry development of fine resist patterns in e‐beam lithography is described. The best resolution obtained is 100 nm in the monolayer process. The electron sattering effects are essential in the limitation of the resolution. The possible application of dry development in e‐beam lithography which overcomes the backscattering limitations is a multilayer resist which gives 100‐nm line and 200‐nm space dry developed patterns by a conventional e‐beam exposure apparatus.

ISSN:1071-1023    

DOI:10.1116/1.583303

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

This paper reports the results of a modulated ion beam study of the ion‐assisted etching of Si using Cl2gas and Ar+ions. These experiments were designed to study the kinetic mechanism of the ion‐enhanced surface reaction of Si with Cl2, which is thought to be responsible for anisotropic etching of Si in practical plasma systems. Pulses of Ar+ions (typically 12 ms long) were incident on the surface with ion fluxes ranging up to 4.5×1014ions/cm2 s and ion energies between 0.3 and 3 keV. Chlorine fluxes were varied between 2×1012and 4×1014molecules/cm2 s. Products were detected with a quadrupole mass spectrometer and a comparison of the resulting modulated signals with the cracking pattern of SiCl4under the same conditions indicated that most of the Si left the surface in the form of SiCl4. The amount of Si removed from the surface depended linearly on the incident ion and increased with increasing chlorine up to a saturation limit. The time dependence of the product signals, measured by signal averaging, is not consistent with physical sputtering. A kinetic mechanism is discussed for this reaction.

ISSN:1071-1023    

DOI:10.1116/1.583304

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Oxidation of tantalum disilicide films deposited by cosputtering on highly phosphorus doped polycrystalline silicon was investigated as a function of various film preparation parameters. The thermal oxides, with a thickness of about 100 nm, were characterized by cross‐sectional TEM, AES, and SIMS depth‐profiling as well as breakdown strength measurements on small‐area and large‐area capacitors. No limitation on oxide growth for dry and steam oxidation was found in the investigated temperature range of 800 to 1000 °C. The removal of the native oxide on the poly‐Si prior to TaSi2deposition by an HF dip or by backsputtering is crucial for reproducible oxide growth. The nature of the oxide is similar to thermal SiO2on (100) Si. The TaSi2film integrity is maintained during oxidation. The high surface and interface roughnesses cause oxide thickness variations of about 50%. A high mass fraction of the order of 0.5 wt.% phosphorus was found in the oxides. The breakdown strength of both steam and dry oxides is about one order of magnitude lower than the values for thermal oxides onn+‐poly‐Si. These low breakdown strength values are attributed mainly to large pores in the oxides observed in the TEM. No restrictions on process compatibility were found.

ISSN:1071-1023    

DOI:10.1116/1.583305

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.583307

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.583308

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

We present a model for the growth of III–V compound semiconductors by molecular beam epitaxy which is based on an atomistic Monte Carlo simulation and a statistical fluctuation theory. This model allows one to understand the microscopic nature of the growth front and the interface as well as to identify the critical kinetic parameters responsible for their quality. We find that under normally employed growth conditions the cation surface migration rate is the most important parameter in controlling the surface and interface quality.

ISSN:1071-1023    

DOI:10.1116/1.583166

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

In this paper two major morphological defects that occur in the growth of GaAs and AlxGa1−xAs by molecular beam epitaxy (MBE) are discussed. A uniform, fine scale (<1000 Å period) roughness found on AlxGa1−xAs wafers grown at certain temperatures is shown to result from the presence of a thin Ga layer that has segregated on the surface during growth. The surface roughness leads to high interfacial recombination velocities at GaAs–AlxGa1−xAs heterojunctions and strongly degrades heterostructure device performance, especially lasers. Larger (<20 μm) but localized (density ∼103–105cm−2) oval defects have been proposed to result from spitting of globules of material from the group III element effusion cells. Here, evidence will be presented in support of this hypothesis. The shape of these oval defects as well as the AlxGa1−xAs surface roughness are shown to be related to the anisotropy of the interfacial energy of the group III elements on GaAs and AlxGa1−xAs.

ISSN:1071-1023    

DOI:10.1116/1.583167

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

In the molecular beam epitaxial (MBE) growth of InxGa1−xAs, quite uniform and lattice‐matched In0.53Ga0.47As epilayers have been obtained over large‐size InP wafers. Composition variation of the epitaxial layer over an entire 2‐in. φ wafer is less than ±0.7%; that is, the difference of lattice mismatch between the center and the edge of the wafer is less than 1×10−3. Around the center, composition variation is less than ±0.25% over lateral dimension of 2.5 cm. In this 2‐in. φ epitaxial wafer, the relation between electron mobility and lattice mismatch is also studied.

ISSN:1071-1023    

DOI:10.1116/1.583168

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

A computer model for the effusion process commonly utilized in molecular beam epitaxy (MBE) is presented. The model is capable of simulating effusion sources of both conical and cylindrical design. The results of the model, for one MBE setup, shows that the gallium flux incident on a 4×4cm area has greater than a 30% variation and the gallium to arsenic ratio incident upon the same region varies by a factor of 2. A gallium arsenide (GaAs) layer was then grown under approximately the same conditions as used in the simulation. Observation of the layer’s thickness and morphology show reasonable agreement with the computer model’s results.

ISSN:1071-1023    

DOI:10.1116/1.583169

出版商:American Vacuum Society    

年代:1985

数据来源: AIP