Abstract: Selective deposition of a refractory metal on a silicon substrate utilizing high temperature and a silane reduction process in which the flow rate ratio of silane to refractory metal halide gas is less than one. In a second embodiment, an additional layer of the refractory metal is deposited utilizing a hydrogen reduction of the metal halide gas at very high temperatures. In both embodiments, a refractory metal barrier layer may be provided by forming a self-aligned refractory metal silicide layer. Alternatively, a two layer self-aligned barrier is formed of a refractory metal silicide lower layer and a refractory metal nitride upper layer and the refractory metal is selectively deposited on the metal nitride.

Abstract: A method of depositing tungsten on a substrate utilizing silicon reduction wherein the process is non-limiting as to the thickness of silicon that may be converted to tungsten. A silicon substrate is provided with at least one area of silicon material having a predetermined thickness and the substrate is exposed to a tungsten hexafluoride gas flow in a chemical vapor deposition environment. By adjusting the WF.sub.6 gas flow rate and the CVD process parameters, such as pressure, temperature and deposition time, the thickness of silicon converted to tungsten can be adjusted in order to convert the entire thickness. A novel structure having a midgap tungsten gate and tungsten source and drain metallized layers is also disclosed.

Abstract: Thin film field effect transistors are disclosed having direct or near direct contact of the source and drain electrodes to the channel region. Inverted gate and non-inverted gate types are fabricated by forming metallic source and drain electrodes within a layer of semiconductor material in contact with the channel region. The electrodes are formed by converting monocrystalline, polycrystalline or amorphous silicon regions to a refractory metal such as tungsten by using a non-self-limiting metal hexafluoride reduction process. The tungsten conversion process is isotropic and provides self-alignment of the source and drain electrodes with the gate in the non-inverted gate TFT. The process is low temperature, allowing the use of amorphous silicon as the semiconductor material. The transistors are especially useful for formation on large glass substrates for fabricating large flat panel displays.

Abstract: A gate structure for integrated circuit devices which includes a work function layer, a low resistivity layer, and an electrically conductive barrier layer between the two other layers to prevent the other two layers from intermixing. The work function controlling layer is preferably selected from the group of tungsten, molybdenum, their silicides, or a combination thereof.

Abstract: A method is described for depositing thick, low-stress refractory metal films on a substrate. For example, a layer of tungsten of any required thickness may be deposited by the silicon reduction of tungsten hexafluoride in a CVD reactor. This is accomplished by alternating the process step of plasma depositing an amorphous silicon film, with the process step of exposing the silicon film to tungsten hexafluoride until the required thickness of tungsten is reached. The thickness of the deposited amorphous silicon film must be less than the thickness at which the replacement of silicon to tungsten becomes self-limiting to assure that all of the amorphous silicon is replaced. The bombardment of the silicon during plasma deposition "hammers" the underlying tungsten film and relieves the stress in the film.

Abstract: A structure and method for fabricating the structure, which includes a layer containing a refractory metal and a substrate to which the refractory metal-containing layer does not strongly adhere, there being a thin bonding layer between the substrate and the refractory metal-containing layer for providing good adherence between the refractory metal-containing layer and the substrate. The bonding layer is an oxide, nitride or mixed oxy-nitride layer initially prepared to be Si-rich in a surface region thereof. Inclusions of the refractory metal are produced in the bonding layer by substituting the refractory metal for excess free silicon therein. These inclusions become nucleation and bonding sites for refractory metal deposition, ensuring good adhesion.

Abstract: A superior wear-resistant coating is provided for metallic magnetic recording layers, where the improved coating is a hard carbon layer that is strongly bound to the underlying metallic magnetic recording layer by an intermediate layer of silicon. The silicon layer can be very thin, with a minimum thickness of a few atomic layers, and provides strong adhesion between the hard carbon protective layer and the metallic magnetic recording layer. A preferred technique for depositing both the intermediate silicon layer and the hard carbon layer is plasma deposition, since both of these depositions can be performed in the same reactor without breaking vacuum.

Abstract: A deposition technique for forming metal regions on semiconductor substrates, and more particularly to a fabrication method for the differential selective deposition of tungsten for forming tungsten contacts on an integrated circuit chip.Tungsten hexafluoride gas (WF6) is introduced into a deposition chamber containing a silicon substrate with an apertured silicon dioxide mask layer thereon. The exposed Si surfaces on which the selective deposition is to be performed, are first converted to W surfaces by the substitution reaction:2WF6+3Si=2W+3SiF4After the surface has been substituted, the WF.sub.6 is mixed with H.sub.2 as to give deposition of W by partially preferential nucleation on the already converted W surfaces. Then NF.sub.3 is bled into the system and a plasma is struck in the reaction chamber to create a simultaneous etching condition for the tungsten.The amount of NF3 and the plasma power coupled into the chamber are such as to ensure that the SiO.sub.2 surface is kept clean at all times.