Hughes Aircraft Company

Timothy T Zielinski

Cheng P Wen

Randy K Rolph

Milton Feng

Victor K Eu

James M Whelan

Multiple solid precursor bubblers are used to alleviate channeling effects caused by high carrying gas flow rates to provide for deposition of indium-based epitaxial materials in high-capacity MOCVD reactor systems. Precracking of precursor materials that exhibit higher dissociation temperatures using heated manifolds or heated susceptor, and rotation of individual wafers in a multi-wafer reactor chamber enhance thickness uniformity, surface morphology and electronic properties of deposited epitaxial layers.

MOCVD reactor system for indium antimonide epitaxial material

A cone-shaped bubbler for use with solid metal organic source material used in metal organic chemical vapor phase deposition systems, and a method of producing carrying gas saturated with source material that is injected into such systems. The bubbler comprises a sealed container having a slanted wall with an inverted cone-shaped cross section. Solid metal organic source material is disposed in the container. A heat bath surrounds the sealed container. A carrying gas inlet is disposed adjacent the top of the container. Carrying gas is injected in a tangential direction relative to the source material, and a whirlpool effect is generated by the tangential gas flow that imparts a centrifugal force to gas molecules, pushing the source material against the wall to promote heat flow from the heat bath to sustain high rate sublimation. A gas outlet is disposed adjacent the bottom of the container. Once source material lining the slanted inner wall is removed, gravitational forces cause source material to refill the empty space, reducing channel formation and preventing thermal isolation of the source material at the center of the bubbler. The method comprises providing a sealed container with a slanted wall having an inverted cone-shaped cross section, disposing solid metal organic source material in the container, heating the sealed container, injecting a carrying gas adjacent the top of the container so that carrying gas is injected in a tangential direction relative to the solid source material, and removing saturated carrying gas from a gas outlet disposed adjacent the bottom of the container.

Bubbler for solid metal organic source material and method of producing

Silicon doping of GaAs epitaxial layers grown using the AsCl.sub.3 /H.sub.2 /GaAs:Ga CVD system is accomplished using AsCl.sub.3 :SiCl.sub.4 liquid doping solutions. These solutions can be readily prepared with reproducible compositions and provide excellent doping control. Fine adjustments in the doping level can be achieved by adjusting the H.sub.2 flow rate and by varying the temperature of the doping solution. Doping levels may range from about 5.times.10.sup.15 to 5.times.10.sup.19 cm.sup.-3 by adjusting the mole fraction of SiCl.sub.4 in the doping solution and the H.sub.2 flow rate to change the mole fraction of P.sub.HCl. The epitaxial layers doped using this technique have excellent room temperature and liquid nitrogen mobilities for electron concentrations between 1.times.10.sup.16 cm.sup.-3 and 8.times.10.sup.18 cm.sup.-3. This doping method is particularly useful for the growth of GaAs epitaxial layers for FET devices.

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Torrance, CA, United States of America

Timothy T Zielinski