摘要:

During reactive ion etching of tantalum silicide and polysilicon layers in a chlorine based chemistry it is observed that a film (15–20 nm) is deposited on vertical surfaces of etched structures. This film is even present after common resist strip processes. This film is analyzed by Auger electron spectroscopy and transmission electron spectroscopy, and the formation mechanism is investigated. It is shown it is composed of silicon dioxide sputtered from dielectric layers lying under the etched silicide and poly Si layers. Variables influencing the formation of the residual sidewall film are analyzed. It is demonstrated that the observed residual films are not involved in the anisotropic etch characteristics before the silicide or poly Si layer are etched through. It is further demonstrated that a carbon based polymer film or inhibition layer must be responsible for the anisotropic etch profile of the tantalum silicide layer. This second carbon based film is formed only with a sufficient amount of photoresist in the etching chamber.

ISSN:1071-1023    

DOI:10.1116/1.584776

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

High‐performance time‐of‐flight secondary ion mass spectrometry (TOF SIMS); characterized by high mass resolution, extremely high sensitivity, and high dynamic range, has been applied to surface analysis of GaAs and Si wafers. Mass separation of metal and hydrocarbon ions of identical nominal masses allows the unambiguous detection of metal contaminants, even in the presence of heavy surface contamination by hydrocarbons. In favorable cases surface sensitivities in the ppm range are achieved. Quantitative element analysis and detection of molecular surface contaminants are possible.

ISSN:1071-1023    

DOI:10.1116/1.584777

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Hydrogenated amorphous carbon layers (a‐C:H) formed by plasma deposition on silicon and germanium substrates have been depth profiled by 5‐keV Ar+sputtering and analyzed with Auger and photoelectron spectroscopy, secondary ion and secondary neutral mass spectroscopy. Reference data have been established for quantitative analysis, compound identification and the exclusion of the experimental artifact of ion‐bombardment induced carbide formation. The composition, binding state and some structural parameters ofa‐C:H layers on Si and Ge substrates have been investigated for various deposition parameters. In each case, a carbidic phase is found in the interface to the substrate. The adhesion of the layers depends mainly on the overlap of this interfacial carbide with the adjacent regions, whereas the hardness of the layers can be characterized by the structure and composition of the layer itself. Changes caused by tempering of the layers are also discussed.

ISSN:1071-1023    

DOI:10.1116/1.584778

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

The etching of SiO2films on a Si substrate in an rf plasma in CF4has been studied withinsituellipsometry. The etch rate was measured as a function of flow, rf power and pressure. An accurate analysis of the experimental data using numerical simulations based on multilayer models has yielded information both on the refractive index of the etched SiO2film and on the existence of a top layer. It could be established that a layer is present on top of the SiO2during etching, which is probably caused by roughening of the SiO2layer. Furthermore at high pressures (>8 Pa) it was demonstrated that after the complete removal of the SiO2film a polymer layer starts growing on the Si substrate.

ISSN:1071-1023    

DOI:10.1116/1.584779

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Dry etching of microstructures in various materials has sometimes resulted in sidewalls which slope away from the mask edge. In this paper we model this phenomenon using a process of simultaneous isotropic deposition and anisotropic etching which has been shown by others to give good qualitative agreement with observed etched profiles. A simple analytical relationship between the etch and deposition rates of the deposited material is given and used to deduce a number of features of sloped sidewall etching. We compare these predictions with some experimental results gained using metal based compounds as the deposit material. We provide evidence suggesting that this metal compound deposition can explain a number of previous observations of sloped sidewalls.

ISSN:1071-1023    

DOI:10.1116/1.584780

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Etching plasmas based on CF4have been studied in a magnetron ion etching (MIE) system. Optical emission and mass spectra were measured as a function of applied power, pressure, and gas composition. Electrical probes were used to measure the plasma floating potential and the dc self‐bias of the rf electrode. The magnetic field has an effect not only on the physics of the plasma (ion density, plasma impedance, etc.) but also on the chemistry. Two regimes of operation are found to exist. Under typical high‐power MIE operating conditions, the species present in the plasma tend to be more highly dissociated than in a conventional reactive ion etching (RIE) plasma. As a consequence, the tendency for C–F polymer to form on etched Si surfaces is suppressed and selective etching of SiO2over Si does not occur. At lower powers, the plasma characteristics and etching response revert back to RIE‐like behavior as the degree of dissociation decreases. The implications for etching processes are discussed.

ISSN:1071-1023    

DOI:10.1116/1.584781

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

In order to apply to neutral beam etching, several hundred eV neutral beams have been generated by charge exchange reaction using a magneto‐microwave plasma ion source. The charge exchange cross sections for Ar+and Kr+are unexpectedly small, whereas the cross section for Ne+of 300 eV is 1.7×10−15cm2in good agreement with published results. The small cross sections for Ar+and Kr+in the present experiments are explained in terms of a nonresonant charge exchange scheme. The capacitance–voltage (C–V) measurements show that the radiation damage to SiO2/Si by Ne0neutral beam bombardment is much less than those by Ne+ion beam and by vacuum ultraviolet photons. Consequently, the neutral beam process is a promising method for charge‐free and low‐damage surface processes.

ISSN:1071-1023    

DOI:10.1116/1.584782

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

A three step, ‘‘profile flexible’’ polycide etch was developed which allowed polycide profiles ranging from vertical to controlled undercut. A pressure controlled HCl+CF4overetch was achieved which enabled profile adjustment as desired. Vertical and undercut (0.25 μ per side) polycide profiles were fabricated and speed comparisons accomplished. The majority of devices with undercut profiles exhibited an increase in speed from 20.8 to 23.8 MHz as compared to those devices with vertical profiles.

ISSN:1071-1023    

DOI:10.1116/1.584783

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Raman scattering spectroscopy is used to probe the surface electrical properties (surface depletion width) of GaAs after dry etching in either a reactive ion etching (RIE) system or a remote plasma system. A variety of etch gases (argon, helium, Freon 12, HCl) and biases (−80 to −350 V) are used to examine physically and chemically induced damage. Through the use of wet etches, the dry etch induced damage was observed to be within ∼300 Å of the surface. In the RIE system, etching with argon and helium causes the depletion width to widen, with helium inducing a greater effect. A remote plasma does not cause a change in the depletion width, indicating an absence of energetically damaging species. In contrast to inert gases, etching with reactive gases in both systems reduces the effective surface charge.

ISSN:1071-1023    

DOI:10.1116/1.584784

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

The conditions of evaporation and condensation of thin layers of arsenous sulfide (As2S3) are described. The difference in the selective dissolution of the illuminated and nonilluminated areas found reveals a possibility for the successful application of As2S3as an evaporated photoresist for microphotolithographic purposes. In this connection the influence of the condensation rate (Vc) and evaporation temperature (tevp) on the selective dissolution is studied. It is shown that the selective dissolution is negligibly influenced by the condensation rate but strongly affected by the temperature of As2S3evaporation.

ISSN:1071-1023    

DOI:10.1116/1.584785

出版商:American Vacuum Society    

年代:1989

数据来源: AIP