Abstract:
Self-aligned fabrication of silicon carbide semiconductor devices is a desirable technique enabling reduction in the number of photolithographic steps, simplified alignment of different device regions, and reduced spacing between the device regions. This invention provides a method of fabricating silicon carbide (SiC) devices utilizing low temperature selective epitaxial growth which allows avoiding degradation of many masking materials attractive for selective epitaxial growth. Another aspect of this invention is a combination of the low temperature selective epitaxial growth of SiC and self-aligned processes.
Abstract:
In one embodiment, a method for treating a silicon-containing surface is provided which includes removing contaminants and/or smoothing the substrate surface by a slow etch process (e.g., about 100 Å/min) is provided which includes removing silicon material while forming a recess within a source/drain (S/D) area on the substrate surface. In another embodiment, a method for cleaning a process chamber is provided which includes exposing the interior surfaces with a chamber clean gas that contains an etchant and a silicon source. The chamber clean process limits the etching of quartz and metal surfaces within the process chamber.
Abstract:
In one embodiment, a method for epitaxially forming a silicon-containing material on a substrate surface is provided which includes positioning a substrate having a monocrystalline surface and a second surface (amorphous or polycrystalline) into a process chamber and exposing the substrate to a deposition gas to form an epitaxial layer on the monocrystalline surface and a polycrystalline layer on the second surface. The deposition gas preferably contains a silicon source and at least a second elemental source, such as a germanium source, a carbon source or both. Thereafter, the method further provides exposing the substrate to an etchant gas such that the polycrystalline layer is etched at a faster rate than the epitaxial layer. The substrate may be sequentially and repetitively exposed to the deposition and etchant gases to form the silicon-containing material. In one example, the deposition gas contains silane and etchant gas contains chlorine and nitrogen.
Abstract:
A substrate carrier for a parallel wafer processing reactor supports a plurality of substrates. The substrate carrier includes a plurality of susceptors, which may be thermal plates or annular rings that are arranged horizontally in a vertical stack. The substrates are mounted between pairs of susceptors on two or more supports provided around the outer periphery of the susceptors. The number of substrates mounted between each pair of susceptors may the same or different but is two or more between at least one pair of susceptors.
Abstract:
Die Aufgabe der Erfindung besteht darin, den Vertikalaufbau der mit Hilfe der Lichtimpulsbestrahlung auszuheilenden heteroepitaktischen Siliziumkarbid auf Silizium- Strukturen so zu modifizieren, dass eine ebene Schmelzfront erreicht wird. Die erfindungsgemäße Lösung beinhaltet, dass unter die Oberfläche des Halbleitersubstrates vor der Lichtimpulsbestrahlung ein den Schmelzpunkt des Substrates erhöhendes Element durch Ionenimplantation eingebracht wird.
Abstract:
The invention relates to substrates of semi-insulating silicon carbide used for semiconductor devices and a method for making the same. The substrates have a resistivity above 106 Ohm-cm, and preferably above 108 Ohm-cm, and most preferably above 109 Ohm-cm, and a capacitance below 5 pF/mm2 and preferably below 1 pF/mm2. The electrical properties of the substrates are controlled by a small amount of added deep level impurity, large enough in concentration to dominate the electrical behavior, but small enough to avoid structural defects. The substrates have concentrations of unintentional background impurities, including shallow donors and acceptors, purposely reduced to below 5°1016 cm-3, and preferably to below 1°1016 cm-3, and the concentration of deep level impurity is higher, and preferably at least two times higher, than the difference between the concentrations of shallow acceptors and shallow donors. The deep level impurity comprises one of selected metals from the periodic groups IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIIIB. Vanadium is a preferred deep level element. In addition to controlling the resistivity and capacitance, a further advantage of the invention is an increase in electrical uniformity over the entire crystal and reduction in the densityof crystal defects.
Abstract:
A method of depositing silicon carbide on a substrate, including placing a substrate in a low pressure chemical vapor deposition chamber; flowing a single source precursor gas containing silicon and carbon into the chamber; maintaining the chamber at a pressure not less than approximately 0,67 Pa (5 mTorr); and maintaining the substrate temperature less than approximately 900°C. The method also includes a method for depositing a nitrogen doped silicon carbide by the addition of nitrogen containing gas into the chamber along with flowing a single source precursor gas containing silicon and carbon into the chamber.
Abstract:
A method is disclosed for preparing a substrate and epilayer for reducing stacking fault nucleation and reducing forward voltage (Vf) drift in silicon carbide-based bipolar devices. The method includes the steps of etching the surface of a silicon carbide substrate with a nonselective etch to remove both surface and subsurface damage, thereafter etching the same surface with a selective etch to thereby develop etch-generated structures from at least any basal plane dislocation reaching the substrate surface that will thereafter tend to either terminate or propagate as threading defects during subsequent epilayer growth on the substrate surface, and thereafter growing a first epitaxial layer of silicon carbide on the twice-etched surface.