摘要:

The damage generated in reactive ion etched Si using CHF3added with O2is studied using a metal-contamination-free reactor. The measurements of the photoconductive decay curve on the etched Si substrates indicate that carrier recombination lifetime decreases as the flow rate of oxygen increases. Physical analysis x-ray photoelectron spectroscopy and secondary ion mass spectrometry show that plasma polymerized film consisting of carbon and fluorine can be seen on the etched Si substrate in the low oxygen flow rate region. The thickness of the film depends inversely on the oxygen flow rate. It becomes clear that thick plasma polymerization film protects the substrate from ion bombardment that results in damage.

ISSN:1071-1023    

DOI:10.1116/1.589257

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

We present a two-dimensional Monte Carlo simulation of profile evolution during the overetching step of polysilicon-on-insulator structures, which considers explicitly (a) electric field effects during the charging transient, (b) etching reactions of energetic ions impinging on the poly-Si, and (c) forward inelastic scattering effects. Realistic energy and angular distributions for ions and electrons are used in trajectory calculations through local electric fields near and in the microstructure. Transient charging of exposed insulator surfaces is found to profoundly affect local sidewall etching (notching). Ion scattering contributions are small but important in matching experimental notch profiles. The model is validated by capturing quantitatively the notch characteristics and also the effects of the line connectivity and open area width on the notch depth, which have been observed experimentally by Nozawa et al. [Jpn. J. Appl. Phys.34, 2107 (1995)]. Elucidation of the mechanisms responsible for the effect facilitates the prediction of ways to minimize or eliminate notching.

ISSN:1071-1023    

DOI:10.1116/1.589258

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

We have used x-ray photoelectron spectroscopy (XPS) to study the chemical constituents present on the surfaces after etching of poly-Si features masked with photoresist or oxide patterns. The wafers were etched in a low pressure, high density plasma, helicon source using a HBr/Cl2/O2gas mixture. The O2gas flow rate was tuned to obtain anisotropic etching profiles by forming an SiO2like layer on the sidewalls of the features and maximizing the polysilicon/gate oxide selectivity. Electrostatic charging of insulating surfaces and geometric shadowing of photoelectrons by adjacent photoresist lines were performed to differentiate the photoemission signals from the tops, sidewalls, and bottoms of the features. XPS analyses have shown that the passivation layer formed on the polysilicon sidewalls during etching is a chlorine rich silicon oxide film with both type of masks. This film contains a low carbon concentration when resist is used as a mask. The similar thickness and constitution of the sidewall for oxide and photoresist masked poly-Si samples indicate that the nature of the mask material has no significant effect on the sidewall passivation mechanism.

ISSN:1071-1023    

DOI:10.1116/1.589259

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

The etch characteristics of GaN, InN, InAlN, AlN, and InGaN were measured for a new plasma chemistry, IBr/Ar, in an electron cyclotron resonance plasma discharge. The effects of plasma composition (12.5%–100% IBr), microwave (400–1000 W) and rf power (50–250 W) on the etch rates for these materials were examined. The etch rates for GaN depended strongly on plasma composition, while the etch rates were only weakly dependent on microwave power in the range 400–800 W for all materials. The etch rates for all materials generally increased with increasing rf power, indicating that higher ion energies are much more efficient in enhancing sputter desorption of the etch products. While the etch rates were slower than with either ICl/Ar or Cl2/Ar, the etched surface of GaN was found to be extremely smooth, with little loss of N from the surface at low rf powers, and no significant residue on the surface.

ISSN:1071-1023    

DOI:10.1116/1.589260

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

The electrical properties of a (100) InP surface were studied based on the fabrication process of a buried heterostructure (BH) laser diode (LD). The current–voltage (I–V) and capacitance–voltage (C–V) characteristics were measured for Schottky barriers on the surface at each step of the process—reactive ion etching (RIE) with a mixture of methane (CH4) or ethane (C2H6) and hydrogen (H2), oxygen plasma treatment, chemical etching, and annealing—under conditions which produce almost the same surface as that immediately before the BH regrowth. From the characteristics, it was found that CH4/H2and C2H6/H2RIEs caused the appearance of almost the same damage layers as a result of phosphorus desorption and hydrogen passivation in the near-surface region. Furthermore, it was found that only annealing can remove the hydrogen passivation. These results suggest that to obtain a high-quality regrowth interface it is essential to chemically etch the damage layers resulting from phosphorus desorption prior to BH regrowth in the fabrication process of BH-LDs.

ISSN:1071-1023    

DOI:10.1116/1.589233

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

We present a quantitative model to understand the ellipsometry traces recorded while etching patterned wafers in a high-density plasma reactor. This model allows one to determine the real-time thickness of a film as it etches, and data are presented showing the real-time thickness of TiN and polysilicon layers while etching. The model is generic to the film type and can be applied to any arbitrary stack of materials. Knowing the thickness in real time allows greater process control, as it enables one to stop or change the process at a specified remaining film thickness. The model is essentially geometric and does not include the effect of diffraction. It has been applied successfully to many samples, each with different integrated circuit layouts. The results are in good agreement with scanning electron microscopy measurements.

ISSN:1071-1023    

DOI:10.1116/1.589234

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

We demonstrate real-time semiconductor processing temperature control based on direct, noninvasive,in situmeasurement of wafer temperature by diffuse reflectance spectroscopy. The precision of the controlled temperature was maintained within±0.5 °C with an update time of 2 s over a temperature range from 25 to 600 °C for semi-insulating GaAs wafers. Direct control of the wafer temperature using diffuse reflectance spectroscopy is compared to the usual situation where the wafer heater temperature is controlled. The direct control of wafer temperature using diffuse reflectance spectroscopy is shown to be a significant improvement over conventional heater control technology in accuracy, stability, repeatability and response rate, for dynamic control of wafer temperature in the range of 25–600 °C. Our technology can also be applied to Si and other semiconductor wafers following appropriate calibration.

ISSN:1071-1023    

DOI:10.1116/1.589235

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

Deposition temperatures in the range of 500 °C are required for aluminum via fill planarization processes. The control of the deposition temperature is a critical factor in achieving consistent via fill planarization. A wafer level technique was developed and proven to be consistent through the operating temperature range to highlight any deviation in the deposition temperature.

ISSN:1071-1023    

DOI:10.1116/1.589236

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

We have used mass spectroscopy to observe and analyze, in real-time, gas phase reactants and product species in plasma enhanced chemical vapor deposition (PECVD) of silicon. We describe a doubly differentially pumped mass spectrometry system to sample the exhaust stream of a large area plasma CVD reactor operating at 0.4–1.5 Torr. We show real-time quantitative analysis of silane consumption and hydrogen production for deposition of hydrogenated amorphous silicon and for pulsed-gas selective area silicon deposition. The ability of mass spectrometry to observe process faults in real time is also demonstrated. Mass spectroscopy is a useful nonintrusive process-state sensor for real-time metrology of plasma deposition, for example, to quantify gas phase species, and to characterize reactions occurring on the substrate surface. Based on our results, we discuss potential advanced manufacturing applications of real-time mass spectrometry in amorphous silicon and selective area silicon plasma deposition, including indirect wafer-state sensing, fault analysis and classification, and run-to-run and real-time process control.

ISSN:1071-1023    

DOI:10.1116/1.589237

出版商:American Vacuum Society    

年代:1997

数据来源: AIP

摘要:

Selective chemical vapor deposition of TiSi2for contacts and interconnects in 0.25μm and below design rule devices has been performed from TiCl4/DCS/H2chemistry using an industrial integrated cluster tool. Selectivity on oxide and nitride and a resistivity of around 16μ cm have been obtained. The growth rates obtained on doped/undoped, poly/mono Si are almost identical. The grain size on poly Si is around 0.10μm. Loading effect has been observed and corrected by the gas mixture. This chemical vapor deposition (CVD) technique has thus been used in a 0.25μm complementary metal–oxide–semiconductor technology and the results are compared with the standard salicide (solid phase reaction) and elevated source/drain/gate (with selective epitaxy) followed by the salicide. The results show that CVD is a most promising process for the 0.2μm technology with higher values for the transistor saturation current.

ISSN:1071-1023    

DOI:10.1116/1.589238

出版商:American Vacuum Society    

年代:1997

数据来源: AIP