Abstract: A process and apparatus for the low pressure, cold wall, chemical vapor deposition of refractory metals, such as tungsten on a silicon wafer. The silicon wafer is introduced into a loading lock wherein the pressure is reduced to subatmospheric pressure. The silicon wafer is transferred to a deposition chamber where it is heated to an elevated temperature. A refractory metal carbonyl vapor is introduced into the deposition chamber and dissociates to deposit a refractory metal on the silicon wafer. The wafer is transferred to an unloading lock where it is allowed to cool and is then removed.

Abstract: A low pressure control system for chemical vapor deposition (CVD) apparatus, including a vacuum pressure chamber and an exhaust pump, is provided by a vacuum pump DC motor which is supplied power from a DC motor speed controller coupled to a DC control input signal from a pulsewidth modulation DC converter. The converter receives a single pulsewidth modulated pulse train having its percentage of modulation controlled in accordance with a DC to pulsewidth modulation controller which operates in accordance with the difference between a pair of DC input signals corresponding to the actual pressure inside the vacuum pressure chamber and a desired or set point pressure respectively. The vacuum pump motor speed and accordingly the exhaust pump is controlled with a high degree of precision, thereby providing improved coating uniformity of semiconductor wafers being fabricated by the CVD apparatus.

Abstract: Thermal CVD process for forming Si.sub.3 N.sub.4 -type films on substrates by reaction of gaseous NF.sub.3 with gaseous disilane at a temperature in the range of 250.degree.-500.degree. C., at pressures of 0.1-10 Torr. The mole ratio of NF.sub.3 to silane is in the range of 0.5-3.0 and the reaction zone is preferably isothermal (T controlled to within .sup.+ 5.degree. C.). The resulting films have RI's in the range of 1.4 to 3.0. The process parameters can be controlled to dope the film with H and/or F, or to create zones of differing properties within the film. The process does not cause radiation damage, metal migration, stored charge dissipation or high levels of impurities. Control of distance between adjacent wafers and wafer-to-wall spacing combined with laminar gas flow gives excellent film thickness uniformity, on the order of below about .+-.5% across the wafer face, both within (across) wafers and from wafer to wafer (batch uniformity).

Abstract: A chemical vapor deposition wafer boat for supporting a plurality of wafers in an evenly spaced, upright orientation perpendicular to the axis of the boat comprises a cylinder having closed ends and comprised of mutually engaging upper and lower hemicylinders. The upper hemicylinder has diffusion zones with gas flow passageways therein in the ends and zones within from 0 to 75 and within from 0 to 15 degrees from a vertical plane through the cylinder axis. The remainder of the hemicylinder wall and the ends are baffle areas without gas flow passageways. The ends and sidewall of the lower hemicylinder comprise gas diffusion zones. The gas flow passageways comprise from 0.5 to 80 percent of the surface area of the respective gas diffusion zones.

Abstract: A chemical vapor deposition wafer boat for supporting a plurality of wafers in an evenly spaced, upright orientation perpendicular to the axis of the boat comprises a cylinder having closed ends and comprised of mutually engaging upper and lower hemicylinders. The upper hemicylinder has diffusion zones with gas flow passageways therein in the ends and zones within from 0 to 75 and within from 0 to 15 degrees from a vertical plane through the cylinder axis. The remainder of the hemicylinder wall and the ends are baffle areas without gas flow passageways. The ends and sidewall of the lower hemicylinder comprise gas diffusion zones. The gas flow passageways comprise from 0.5 to 80 percent of the surface area of the respective gas diffusion zones.

Abstract: A chemical vapor deposition wafer boat for supporting a plurality of wafers in an evenly spaced, upright orientation perpendicular to the axis of the boat comprises a cylinder having closed ends and comprised of mutually engaging upper and lower hemicylinders. The upper hemicylinder has diffusion zones with gas flow passageways therein in the ends and zones within from 0 to 75 and within from 0 to 15 degrees from a vertical plane through the cylinder axis. The remainder of the hemicylinder wall and the ends are baffle areas without gas flow passageways. The ends and sidewall of the lower hemicylinder comprise gas diffusion zones. The gas flow passageways comprise from 0.5 to 80 percent of the surface area of the respective gas diffusion zones.

Abstract: A chemical vapor deposition wafer boat for polysilicon deposition in a vertical CVD apparatus comprises upper and lower, mutually engaging, open ended hemicylinders. Gas flow passageways are present in a diffusion zone of the lower hemicylinder wall, but not in the remainder of the walls of the hemicylinder. Gas flow to the wafers is limited to diffusion flow, and the wafers are protected from particulates forming in the gas stream during the coating operation.

Abstract: A chemical vapor deposition device having uniformly distributed heating means substantially surrounding an inner deposition reaction chamber for providing isothermal or precisely controlled gradient temperature conditions therein, the reaction chamber being surrounded by the walls of an outer vacuum chamber spaced therefrom.

Abstract: A chemical vapor deposition device having uniformly distributed heating means substantially surrounding an inner deposition reaction chamber for providing isothermal or precisely controlled gradient temperature conditions therein, the reaction chamber being surrounded by the walls of an outer vacuum chamber spaced therefrom.

Abstract: An improved chemical vapor deposition device having heating means substantially surrounding an inner deposition chamber for providing isothermal or precisely controlled gradient temperature conditions therein. The internal components of the chamber are quartz or similar radiant energy transparent material. Also included are special cooling means to protect thermally sensitive seals, structural configurations strengthening areas of glass components subjected to severe stress during operation, and specific designs permitting easy removal and replacement of all glass components exposed to deposition gas.

Abstract: A controlled temperature deposition device comprising an inner reaction chamber having gas distribution means for introducing gas into inner chamber and removing gas therefrom and a vacuum chamber means surrounding the inner deposition chamber and spaced from the walls thereof for maintaining a medium vacuum therein. Associated with the deposition device is a substrate loading and unloading fork which transfers substrates such as wafer boats from outside the device to a position in the inner deposition chamber and removes them from the inner deposition chamber following deposition.