摘要:

A specific criterion for judging whether the resist heating effect will occur under given beam and resist conditions is proposed. The criterion is directly applicable to direct‐writing variably shaped electron‐beam systems and chain‐scission type resists. After studying the relationship between resist temperature and pattern deformation, it is hypothesized then verified experimentally that pattern deformation occurs when temperature at the shot edge point is higher than the glass transition temperature of the resist. Experiments revealed that chemically amplified resists are more resistant to the resist heating effect than chain‐scission type resists. Applying the hypothesis to resist temperature calculations, a constant figure was derived that represents the criterion for high‐throughput writing systems. The figure suggests the beam and resist conditions that are required for high‐throughput pattern writing without the resist heating effect.

ISSN:0734-211X    

DOI:10.1116/1.585824

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Modeling of resist heating for 50‐ and 100‐kVe‐beam exposures of single layer resist on silicon wafers and quartz mask plates is reported. The resist heating from energy dissipation in both the thin resist layer itself and the underlying substrate has been taken into account. A variety of single spot exposure situations are considered to put forward the main features for minimization of thermal effects. Modeling results are compared with experimental results reported in literature. The future perspective for resist heating control in high throughpute‐beam writing is illustrated with a practical example.

ISSN:0734-211X    

DOI:10.1116/1.585825

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Films of palladium acetate Pd(OOCH3)20.1 and 0.3 μm thick have been stoichiometrically altered through exposure to electron beams of 1–30 keV. The lowest required doses for alteration, 1000 and 2500 μC/cm2, were obtained using beam energies of 4 and 5 keV, respectively. These results have been related to Monte Carlo simulations of energy absorbed within a thin surface film. The minimum line widths of features produced was less than 100 nanometers with estimated Pd/C ratio of 1 and measured resistivities as low as 100 μΩ cm.

ISSN:0734-211X    

DOI:10.1116/1.585826

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

High energy focused ion beam implantation of Ga is used to interdiffuse AlGaAs/GaAs quantum wells. Results from low temperature cathodoluminescence, time‐decay photoluminescence measurements and photolumuniscence excitation spectroscopy indicate a good quality of the interdiffused quantum wells. The broadened luminescence peaks are explained by spatial inhomogeneities of the interdiffusion. Quantum boxes were fabricated and studied by cathodoluminescence line scanning. The introduction of a few monolayers of InGaAs close to the quantum well resulted in a remarkable improvement of the homogeneity of the interdiffusion.

ISSN:0734-211X    

DOI:10.1116/1.585827

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Direct writing of metal features narrower than 100 nm is accomplished by scanning a focused ion beam over a substrate covered with a thin solid metalorganic film. A metalorganic cluster coordination compound [Ir4(CO)11Br][N(C2H5)4] is spun on an oxidized silicon wafer from acetone solution and the resulting layer is irradiated with a focused 20 keV Ga‐ion beam. The partially decomposed irradiated film regions show a marked decrease of solubility in acetone. Developing by dissolving the nonirradiated parts of the surface hence leaves narrow lines of partially reacted metalorganic precursor. High temperature treatment of these lines, either in vacuum or in a reactive gas stream, completes the decomposition to quite pure iridium, as is confirmed by micro‐Auger analysis. In these preliminary experiments we obtained lines with room temperature electrical resistivities as low as 400 μΩ cm, at direct writing speeds of 40 μm s−1to 0.8 mm s−1, which correspond to ion doses of 3.1×1016ions/cm2to 1.6×1015ions/cm2, respectively. The width of the metal lines decreases with decreasing ion dose in this range from 180 down to 90 nm. The adhesion to the substrate increases with increasing ion dose. The thickness of the resulting iridium lines depends mainly on the thickness of the metalorganic precursor layer. The maximum possible thickness of the [Ir4(CO)11Br][N(C2H5)4] layer that can be used depends on the effective penetration depth of the ions in this layer.

ISSN:0734-211X    

DOI:10.1116/1.585828

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The transport and behavior of particulates during plasma processing is imaged in real time using rastered laser light scattering combined with video detection. Results show the distribution of particles is highly ordered and predictable. Two effects have major influence on the distribution and location of particles: feed gas drag and electrostatic traps. Particle traps form from plasma disturbances and design properties of the electrode and the tooling. These results are confirmed in normal plasma conditions used in microelectronics fabrication. A strategy is presented for plasma contamination control. Complete elimination of trapping effects is not feasible. Instead, process techniques are used to minimize or defeat the attractive nature of the traps. Several examples are discussed.

ISSN:0734-211X    

DOI:10.1116/1.585829

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

This paper describes the first results of the new Leybold Leybold circular electron cyclotron resonance (CECR) technology which uses circular polarized microwave excitation for generating a plasma of very high density. At a pressure of 1 μbar, an ion current density of 6 mA/cm2was measured in a pure chlorine plasma. That reveals in fact an increase of about 30% in ion density compared to the linear polarized electron cyclotron resonance (ECR) source. The appreciable improvement will be demonstrated by etching results of silicon trench with chlorine where an etch rate of 300 nm/min with a uniformity better than ±5% on 200 mm wafer size was obtained. The source has a compact design which enables multichamber processing in a cluster tool environment with the capability for processing wafers up to 200 mm diameter.

ISSN:0734-211X    

DOI:10.1116/1.585830

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

HCl radical beam etching has been used to produce strain‐induced lateral confinement of excitons in a GaAs quantum well. This confinement was generated by etching a grating pattern into a strained layer of In0.35Ga0.65As which overlies the GaAs quantum well. Atomic force microscopy was used to examine the etched surface morphology. Photoluminescence and excitation photoluminescence spectroscopy were used to detect the optical transitions. The after‐etch photoluminescence intensity and the systematic peak shift with etch time indicate the degree of control and low‐damage nature of the etch process used.

ISSN:0734-211X    

DOI:10.1116/1.585831

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We report the preparation of GaAs substrates, using only electron cyclotron resonance plasma techniques, and the subsequent growth of GaAs by molecular beam epitaxy, accomplished within an integrated processing facility. Exposure of the substrates to a hydrogen plasma with an ion current density less than 3 mA/cm2for 1 h removes the native GaAs oxide leaving a smooth crystalline surface as revealed by streaky (1×1) reflection high energy electron diffraction patterns. At a greater ion current density a spotty diffraction pattern is obtained; a subsequent SiCl4plasma etch restores a streaky (1×1) diffraction pattern. After plasma processing, evidence of surface reconstruction is observed at substrate temperatures greater than 400 °C in an As overpressure and during GaAs overgrowth. Impurity concentrations at the epilayer/substrate interfaces of plasma‐prepared samples are found to be comparable to those of chemically prepared wet etched substrates. This vacuum substrate preparation scheme is a first step toward realizing the benefits of integrated device processing.

ISSN:0734-211X    

DOI:10.1116/1.585832

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

A new gate fabrication technique has been developed based on focused ion beam exposure and reactive ion etching of a polymethylmethacrylate (PMMA)/Ge/PMMA multilevel resist structure. The focused ion beam exposes the thin PMMA imaging layer that is transferred directly to the germanium layer using reactive ion etching (RIE). The underlying resist is etched first in oxygen at high pressure, providing an undercut, bowl‐shaped profile, followed by an extremely low pressure, anisotropic oxygen process, which etches a narrow stem down to the base of the resist, resulting in a chalice‐shaped profile. Removing the germanium layer allows the profile to be used to lift off the Ti/Pt/Au gate. This process is compatible with our self‐aligned gate high electron mobility transistor (HEMT) process and provides an alternative technique for gate fabrication below 75 nm. Focused ion beam gate structures have been fabricated with 60 nm gate length and 0.15 μm2cross section using this technique and shown that the resulting gate profile can be used to shadow a 200 nm thick Ohmic contact evaporation to form the self‐aligned structure with a source/drain spacing of 225 nm. It has also been determined that ion bombardment damage to the HEMT channel during RIE can be eliminated by limiting the plasma potential to less than 45 V.

ISSN:0734-211X    

DOI:10.1116/1.585833

出版商:American Vacuum Society    

年代:1991

数据来源: AIP