Diameter Si Wafers Research Articles

Silicon dioxide film deposited by photoassisted microwave plasma CVD using TEOS

High-quality SiO 2 films were conformally deposited on an Al-patterned 6 inch diameter Si wafer at a high deposition rate of 150 nm/min by a photoassisted microwave plasma CVD method using tetraethyl orthosilicate (TEOS) at 250°C. Oxygen gas was excited in a high-density microwave plasma which was generated with cylindrical leaky waveguide and was kept apart from the substrate. Excited oxygen reacted with TEOS gas to generate reactive intermediates. The adsorbed intermediates migrated sufficiently for conformal coverage on the substrate surface and were photoexcited with an extra-high pressure mercury lamp to produce high-quality SiO 2 films. Aluminum steps were successfully planarized with the high-quality SiO 2 film.

Characteristics of a plasma doping system for semiconductor device fabrication

A plasma doping system for semiconductor ion implantation is described. The target to be implanted is placed directly in the plasma and then biased to a negative potential to accelerate the positive ions into the target. A wafer bias of up to −5 kV with a BF3 source gas are used to implant boron ions into 150 mm diameter Si wafers. Data are presented showing sub-100 nm shallow p+–n junction with good sheet resistance uniformity and dose control repeatability. A high dose rate of ≳1015 cm−2 per minute at low energy (<5 keV) can be readily achieved. Excellent charging test device performance as well as surface contamination control are discussed. All of these results demonstrate the attractiveness of this unique alternate doping technique.

Liquid phase epitaxy centrifuge for 100 mm diameter Si substrates

In a novel centrifuge, we perform silicon liquid-phase epitaxy (LPE) on 100 mm diameter Si wafers. The epitaxial Si layers grow from indium solutions. The thickness uniformity of the layers is better than ±4.9% within the central circular area of 90 mm in diameter. The layers show smooth surfaces. The bulk of the layers is free of extended defects and of solution inclusions. Hall effect measurements and transmission electron microscopic observations confirm the high quality of this epitaxial material.

Metal Organic Chemical Vapor Deposition of Al and CuAl Alloy Films in a Vertical, High-Speed, Rotating Disk Reactor

ABSTRACTA vertical high-speed, rotating disk reactor has been used to produce Al and CuAl alloy films on 125 mm diameter Si (100) wafers. Trimethylamine-alane and Cu (hexafluoroacetylacetonate) trimethylvinylsilane (CupraSelect™) were used as metal precursors. Aluminum films were deposited over the temperature range from ∼100 C to 700 C. Aluminum sheet resistance measurements showed the films to have resistance 2 to 3 times that of bulk Al films. CuAl alloy films were deposited sequentially and by codeposition. At 30 Torr, deposition rates as high as 3.7 um/hr, 0.024 um/hr, and 1 um/hr for Al, Cu, and CuAl films, respectively, were demonstrated. Auger analysis showed the deposited films to be free of contaminants.

Channeling implantation of B and P in silicon

Highly uniform profiles of B and P ions have been obtained by channeling implantations in 150 mm diameter Si(100) wafers. Large differences in penetration depth, doping depth profiles and implantation damage are observed between implantations under channeling and random conditions for a wide range of doses and ion energies using Rutherford backscattering spectrometry, cross-sectional transmission electron microscopy and secondary-ion mass spectrometry.

A New Approach for Low Defect Density GaAs On Patterned Si Substrates by Mocvd

High quality GaAs films have been deposited on sawtooth-patterned (0.2 μm period) Si substrates by MOCVD. Three inch diameter Si wafers were patterned using a combination of holographic lithography and wet chemical etching. A two-step deposition process was used resulting in planar films with surface morphology comparable to films deposited on unpatterned substrates. The initial low temperature nucleation layer was found to be amorphous and conformed to the patterned Si surface. Rapid thermal annealing and thermal cycle growth resulted in substantial reduction in the threading defect density. The MOCVD growth and characterization of these films and the possible mechanisms responsible for the reduction/elimination of the defects at the GaAs/Si interface are discussed.

Elastic Recoil Detection Analysis of the Concentration and Thermal Release of Hydrogen in a-Si:H Films by the ECR Plasma CVD Method

For the a-Si:H films prepared by ECR plasma CVD, the hydrogen content and its variation associated with heat treatment have been studied by means of 6.06 MeV-19F-ERDA. It was found that as the deposition temperature was elevated from room temperature(RT) to 573 K, the hydrogen content in the film abruptly decreased. The activation energy for detrapping was estimated to be 0.84±0.02 eV for the Si-H bonds of two films prepared at RT and at 573 K. For a film prepared on a 5-in.-diameter Si wafer at RT, the film thickness was uniform in the error range of ±3% within the distance from the center to the edge of the wafer, while the hydrogen content fluctuated over the range of 20% near the edge.

Characterization of mirror-like wafer surfaces using the magic mirror method

An awe-inspiring mirror used for centuries in religions of the Far East has been polished and brushed up to become a powerful scientific tool. This “magic mirror”, very simple and non-destructive, transforms latent damage, scratches, waviness and other flaws on mirror-like surfaces into visual images using the “Makyoh” principle. The technique detects undulations of a few nm over a distance of about 0.5 mm. It has recently been used to characterize highly finished mirror-polished large diameter Si wafers for ULSI applications, replacing the laborious and unstable naked eye wafer inspection lines. Our studies have shown that the technique is also very useful for monitoring surface sensitive IC processes such as epitaxy, chemical vapor deposition, rapid thermal process, ion implantation, etc.

Analysis of transition metal induced surface defects in silicon following apid thermal processing

Rapid Thermal Processing(RTP) is extensively used in VLSI technology for implant activation, licidation, oxidation, and passivation glass reflow. The diffusion of back-side depositions of transition metals during rapid thermal annealing and the resulting front-side defect formation in silicon has recently been investigated by several authors but a detailed analysis of the defect structure, morphology, and chemistry is lacking. The defect structure and chemistry on both the front and back sides of the wafers ter RTA were investigated by TEM on plan-view and cross-section foils. A Philips EM430 microscope ierating at 300 KeV and a Hitachi H-800 microscope operating at 200 KeV were used. Ni and Cu sputter deposited on the back-side of 4 inch diameter (100) Si wafers were diffused for 10 sec at 1150°C in trogen ambient. The thickness of the metal film was 50 nm. A Heatpulse 2101 RTA system was used.Fig. 1 is a CDF micrograph showing a group of precipitates on the front surface of a sample nickel diffused from the back surface.