NOVELTY - The heat exchanger (100) comprises a housing (110) having an interior surface (116) and an external surface (118), a first tube (200) disposed in the interior surface of the housing, a heater (120) disposed in thermal communication with the first tube and the housing and configured to heat the first tube, spherical shaped non-reactive members disposed in an interior cavity of the first tube in an arrangement such that voids are defined between the non-reactive members and the first tube, and a heat transfer media that is disposed in the interior of the housing.    USE - The heat exchanger is useful for vaporizing a liquid such as liquid trichlorosilane (claimed) for manufacturing silicon-containing devices e.g. semiconductor wafers or solar cells.    ADVANTAGE - The heat exchanger can be easily, economically and efficiently produced with high thermal conductivity, increased surface area and reduced size, and is capable of effectively vaporizing the liquid trichlorosilane thus effectively and economically manufacturing the silicon-containing devices.    DETAILED DESCRIPTION - The heat exchanger (100) comprises a housing (110) having an interior surface (116) and an external surface (118), a first tube (200) disposed in the interior surface of the housing, a heater (120) disposed in thermal communication with the first tube and the housing and configured to heat the first tube, spherical shaped non-reactive members disposed in an interior cavity of the first tube in an arrangement such that voids are defined between the non-reactive members and the first tube, a heat transfer media that is disposed in the interior of the housing and partially surrounds the first tube, first spherical members disposed in the interior cavity of the first tube in an arrangement such that the voids are disposed between the spherical members and the first tube, a second tube (210) that is disposed in the interior of the housing and has an inlet configured for introducing a flow of liquid into the second tube and an outlet, and a second spherical members disposed in an interior cavity of the tube in an arrangement such that second voids are disposed between the second spherical members and the second tube. The tube: has an interior cavity, and an inlet and an outlet each spaced outward from the external surface of the housing; and is disposed in the interior surface of the housing in a helical arrangement. The inlet is configured for introducing a flow of the liquid into the tube. The arrangement of the non-reactive members permits the liquid to pass through the voids and to travel from the inlet of the tube to the outlet of the tube. The non-reactive members and a hollow tube transfer heat to the liquid as the liquid passes through the voids to partially vaporize the liquid. The non-reactive members include a metal. Each of the non-reactive members has a diameter that is less than half a diameter of the tube. The arrangement of the first and second spherical members permits the liquid to pass through the first and second voids and to travel from the inlet of the first and second tubes to the outlet of the first and second tubes. The spherical members and the tubes are configured to transfer heat to the liquid as the liquid passes through the first and second voids to partially vaporize the liquid. The spherical members together have a volume of 30% of a volume of the tube. The heater is configured to heat the tube, is disposed adjacent to the housing, and is positioned adjacent to the exterior surface and/or the interior surface of the housing. Each of the spherical members has a diameter that is less than 25% of the diameter of the tube. The second tube has an interior cavity. An INDEPENDENT CLAIM is included for a method of vaporizing a liquid trichlorosilane.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of a heat exchanger.    Heat exchanger (100)    Housing (110)    Interior surface (116)    Exterior surface (118)    Heater (120)    First and second tubes. (200, 210)