Patent Publication Number: US-2023160064-A1

Title: Bottom fed sublimation bed for high saturation efficiency in semiconductor applications

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 17/367,284, filed Jul. 2, 2021, the entire disclosure of which is hereby incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to ampoules and methods for using ampoules for semiconductor manufacturing precursors. In particular, the disclosure relates to ampoules and methods to provide bottom fed sublimation bed and tortuous flow path for low vapor pressure precursors. 
     BACKGROUND 
     The semiconductor industry is using an increasing variety of chemistries for chemical vapor deposition (CVD) and atomic layer deposition (ALD) processes that come in liquid or solid form. The precursor is typically inside a closed vessel or ampoule with a single inlet and a single outlet. 
     Solid precursors with a low vapor pressure frequently use a carrier gas to carry the vapor out of the ampoule to the process reactor. For these types of processes there are two types of ampoules typically used: a bubbler where the inlet carrier gas goes into a tube that is submerged into the precursor; and a cross-flow ampoule where the carrier gas sweeps headspace in the ampoule from the top. Often, there is only a very short flow path for the carrier gas. The short flow path from the inlet to the outlet of the vessel does not allow adequate residence time within the vessel to allow the carrier gas to become fully saturated with vaporized or sublimed precursor. Some existing ampoule designs do not evenly distribute the carrier gas across the entire surface of the precursor. Some existing ampoules designs do not provide adequate heating of the precursor within the entire vessel. Many other solid source ampoules do not provide a means for keeping precursor dust from traveling downstream where it hampers control valve performance or creates on-wafer particle issues. 
     Conventional top-fed sublimation architectures include an ampoule or cannister partially filled with solid precursor, which rests on the bottom of the ampoule. As the ampoule is heated and carrier gas is introduced into the head space of the ampoule, sublimation occurs between the top surface of the solid precursor and the carrier gas within the head space. In an ideal scenario, the carrier gas flowing through the ampoule becomes saturated with the precursor. As the head space of the ampoule increases, resulting in varying concentrations of saturated carrier gas, an inconsistent dose of precursor-carrier gas is supplied. As such, carrier gas saturation is not maintained due to inefficiencies in the ampoule and solid precursor depletion. 
     There is a need in the art for ampoules, methods of making ampoules and/or methods of using ampoules with one or more of an increased flow path, increased surface area for sublimation and for consistent concentrations of saturated carrier gas. 
     SUMMARY 
     One or more embodiments are directed to an ampoule for a semiconductor precursor material having a torturous path for increased dwell time in a bottom-fed configuration. The ampoule comprises an outer cylindrical wall, an inner cylindrical wall, a bottom wall, an outlet conduit and a lid. 
     The outer cylindrical wall has an inside surface and an outside surface. The inner cylindrical wall has an inside surface and an outside surface, the inner cylindrical wall having an outer diameter less than an inner diameter of the outer cylindrical wall to form an inlet channel between the inner cylindrical wall and the outer cylindrical wall. The bottom wall has a top surface with a plurality of concentric elongate walls, each wall comprising an opening offset from the opening in adjacent walls. The outlet conduit has an inside surface and an outside surface and an outer diameter less than the inner diameter of the inner cylindrical wall to form a cavity and an inner diameter defining an outlet channel. The lid has a bottom surface in contact with one or more of the outer cylindrical wall, the inner cylindrical wall or the outlet conduit to enclose the inlet channel and the cavity, the lid having an inlet opening in fluid communication with the inlet channel and an outlet opening in fluid communication with the outlet conduit. 
     In some embodiments, the ampoule further comprises a filter media in contact with a top surface of each of the concentric elongate walls. In some embodiments, a gas exchange zone is formed between the filter media, the plurality of concentric elongate walls and the bottom wall, the exchange zone forming a torturous path for a gas to flow from the inlet channel to the outlet conduit. In some embodiments, a solid precursor rests above the filter media, such that depletion of solid precursor does not cause concentration variations within the gas exchange zone. In some embodiments, the filter media is secured between an outer retention ring and a bottom surface of the inner cylindrical wall, and in further embodiments, the filter media is secured between an outer retention ring and a bottom surface of the inner cylindrical wall. 
     In some embodiments, the outer retention ring is fastened to the bottom surface of the inner cylindrical wall by a plurality of fasteners. In some embodiments, the filter media is secured between an inner retention ring and a bottom surface of the outlet conduit. 
     In some embodiments, a bottom end of the inner cylindrical wall includes an inner sloped flange. In some embodiments, the outer cylindrical wall is integral with the bottom wall. In some embodiments, the outer cylindrical wall is removably secured to the bottom wall by a plurality of fasteners. 
     In some embodiments, the outlet conduit is integral with a bottom surface of the lid. In some embodiments, the inner cylindrical wall is integral with the bottom surface of the lid. 
     In some embodiments, the ampoule further comprises a top wall integral with a top surface of the inner cylindrical wall, the top wall having a top surface in contact with the bottom surface of the lid. 
     In some embodiments, a top surface of the outer cylindrical wall includes a groove having an O-ring. 
     In some embodiments, a flange extends outward from a top surface of the outer cylindrical wall, the flange in contact with the bottom surface of the lid. 
     Further embodiments comprise a bottom wall having a top surface with a plurality of concentric elongate walls, each wall comprising an opening offset from the opening in adjacent walls, the bottom wall having a diameter greater than the inner diameter of the outer cylindrical wall, the outer cylindrical wall removably secured to the bottom wall by a plurality of fasteners. 
     Some embodiments are directed to a method of saturating a carrier gas comprising the steps of introducing a carrier into an ampoule by an inlet channel; pushing the carrier gas into a gas exchange zone, the gas exchange zone formed between a plurality of concentric elongate walls protruding from a bottom wall and a filter media positioned over a plurality of concentric walls; saturating the carrier gas with vaporized precursor within the gas exchange zone by passing the carrier gas through an inlet of an outermost elongate wall of the plurality of elongate walls to an outlet of an innermost elongate wall of the plurality of elongate walls; and ejecting the carrier gas through an outlet conduit. 
     In some embodiments, the method further comprises heating solid precursor solid precursor such vaporized solid precursor passes through the filter media. 
     In some embodiments, the exchange zone forms a torturous path for the carrier gas to flow from the inlet channel to the outlet conduit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
         FIG.  1    illustrates a schematic view of an ampoule having a torturous flow configuration in accordance with an embodiment of the present disclosure; 
         FIG.  2    illustrates a cross-sectional view of an ampoule having a torturous flow configuration in accordance with an embodiment of the present disclosure; 
         FIG.  3    illustrates a detailed cross-sectional view of illustrating a bottom wall removably fastened to an outermost wall of the ampoule; and, 
         FIG.  4    illustrates a bottom view of an ampoule having a torturous flow configuration in accordance with an embodiment of the present disclosure. 
     
    
    
     In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. The cross-hatch shading of the components in the figures are intended to aid in visualization of different parts and do not necessarily indicate different materials of construction. 
     DETAILED DESCRIPTION 
     Before describing several exemplary embodiments of the invention, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways. 
     Some embodiments of the disclosure advantageously provide a long flow path for a carrier gas from ampoule inlet to outlet for the delivery of low vapor pressure precursors, e.g., liquid and/or solid source precursor. Low vapor pressure precursors are understood to refer to materials that do not readily vaporize under atmospheric conditions. Low vapor pressure precursors typically have a vapor pressure of less than 10 Torr, and more typically less than 1 Torr. In some applications, a carrier gas is used to deliver low vapor pressure material from an ampoule to a reactor. Low vapor pressure materials typically require heat to increase the vapor pressure. A non-limiting list of exemplary precursors includes ZrCl 4 , Y(EtCP) 3 , HfCl 4 , WCl 5 , MoCl 5 , In(CH 3 ) 3 , and liquid SiI 4 , Mg(Cp) 2 . 
     A flow path having a long and torturous distance allows the carrier gas adequate residence time to become partially to nearly to fully saturated with vaporized and/or sublimed and/or entrained precursor. As used herein, the term “torturous path” means a flow path that has multiple branches, curves, angles, turns, etc., that prevent a straight path for the flow. In some embodiments, the torturous path increases the residence time of the gas within the manifold to increase concentration uniformity. Reference herein to “saturated” allows for varying degrees of saturation. 
     Some embodiments of the disclosure advantageously provide bottom-fed ampoule configurations. Some embodiments advantageously provide ampoules in which depletion of the solid precursor does not affect the concentration of the saturated carrier gas. 
     Some embodiments provide apparatus and methods for heating low vapor pressure precursors in large volume ampoules, including ways to provide effective uniform heating of the precursors. Some specific embodiments advantageously retain low vapor pressure precursors, including solid precursor dust, within a cavity of the vessel, not allowing it to migrate upstream or downstream to control valves by means of filter media. Some embodiments advantageously control uneven depletion of the precursor. Some embodiments advantageously provide even distribution of the carrier gas along the entire surface of a precursor bed in a bottom-fed configuration. Embodiments herein provide improved doses of the precursor. 
     In some embodiments, the ampoules comprise a bottom wall having a plurality of elongate walls defining a labyrinth such that the flow path is tortuous. Advantageously, one or more embodiments provide a flow path whose distance can be five to ten times longer than distances found with common ampoules, in particular solid source sublimation vessels. The increased flow path allows for a longer dwell time of carrier gas and vaporized precursor chemistry to mix within the ampoule. 
     Ampoules disclosed herein comprise a container defining a cavity configured to hold a precursor; an inlet port and an outlet port, both in fluid communication with the cavity; and a bottom wall having a serpentine base. The serpentine base comprises a plurality of elongate walls arranged to define torturous flow channels (also referred to a “serpentine path”), each of the elongate walls comprising a plurality of openings. A flow path is defined by the flow channels and the plurality of openings, through which a carrier gas flows in contact with vaporized or sublimed precursor. 
     Ampoules disclosed herein are in a bottom-fed configuration such that the precursor is separated from a lower chamber by a sublimation bed defined by a filter media. In such a configuration, the gas exchange zone below the filter media maintains a constant volume as precursor resting above the filter media is depleted as carrier gas passes across the filter media. The gas exchange zone is configured to increase the dwell time of carrier gas and vaporized precursor chemistry to mix within the ampoule. 
     Carrier gas passes across the sublimation bed in the gas exchange zone where the precursor chemistry and the carrier gas mix and flow to form a saturated gas mixture of precursor and carrier gas. Carrier gas is streamed directly across the filter media in order to saturate the carrier gas with precursor particles. In some embodiments, the carrier gas flows through a torturous path positioned within the gas exchange zone. The torturous path and the gas exchange zone is configured to increase the duration in which the carrier gas is interacting with precursor chemistry to promote increased saturation of the carrier gas with vaporized precursor. 
     Generally, the flow paths provided herein force the carrier gas to flow around a series of elongate walls, which in one or more particular embodiments are nested concentric tubes having one or more plurality of openings passageways, which define flow channels. The gas flow changes direction from flow channel to flow channel until the last flow channel in communication with the outlet port is reached. This change of direction also enhances mixing of the vaporized and/or sublimed precursor with the carrier gas. Plurality of openings are offset from one another allow the carrier gas to flow through into the next flow channel creating a torturous path. As the carrier gas passes from an inlet opening of an outermost elongate wall through the gas exchange zone, through an outlet opening of an innermost elongate wall, pure carrier gas becomes partially saturated and then fully saturated with precursor chemistry before exiting through the outlet of the ampoule. 
     Reference herein to gas flow includes the carrier gas alone or in combination with entrained and/or vaporized and/or sublimed precursor. The flow paths of the gas exchange zones described herein, for example, in  FIGS.  1 ,  2  and  4    comprise a series of elongate walls, tubular or otherwise, with plurality of openings offset from one another configured to define flow channels therebetween will result in a desired flow path. In some embodiments, as shown in  FIG.  4   , each of the elongate walls comprise one opening offset from an opening of an adjacent elongate wall configured to define flow channels therebetween will result in a desired flow path. In some embodiments, the plurality of openings are off-set to ensure no flow channels are bypassed. Such a configurations are referred throughout the disclosure as “serpentine path” or “torturous path” interchangeably. 
       FIGS.  1  through  3    illustrate schematic representations of an ampoule for a semiconductor precursor material having one or more components separable or integral with one another, with a bottom wall of the ampoule comprising a plurality of concentric elongate walls forming a torturous path. In  FIG.  3   . the bottom wall is a separate component from an outer cylindrical wall such that the ampoule can be filled with solid precursor, the filter media can be serviced, and the ampoule can be cleaned.  FIG.  4    illustrates a top view of the bottom wall showing a torturous flow path configuration in accordance with one or more embodiments. 
     The ampoules described herein are suitable for use with semiconductor manufacturing raw materials, which include reagents and precursors. In the embodiments shown, the precursor is suspended above a filter media configured as a sublimation bed. The general region above the filter media is defined by a cavity for holding solid precursor. The general region below the filter media is characterized as a gas exchange zone in which saturation of the carrier gas occurs. Pure or unsaturated carrier gas first passes from an inlet channel formed between the inner cylindrical wall and the outer cylindrical wall to an opening of an outermost wall of a plurality of concentric elongate walls. The carrier gas is streamed across the filter media and through the torturous path until it passes through an opening of an outermost wall of the plurality of concentric elongate walls. The carrier gas is then expelled through an outlet conduit. 
     As shown in  FIGS.  1  and  2   , the ampoule  100  comprises an outer cylindrical wall  110  with an inside surface  112  and an outside surface  114  and an inner cylindrical wall  120  with an inside surface  122  and an outside surface  124 , the inner cylindrical wall  120  having an outer diameter ROD less than an inner diameter RID of the outer cylindrical wall  110  to form an inlet channel  130  between the inner cylindrical wall  120  and the outer cylindrical wall  110 . In some embodiments, the outer cylindrical wall  110  and inner cylindrical wall  120  are concentric such that gas flowing through the inlet channel  130  flows from an inlet opening  176  towards a bottom wall  140  of the ampoule  100 . In some embodiments, the inlet opening  176  is integral to a lid  170  as explained in further detail below. The inlet opening  176  is in fluid communication with the inlet channel  130  and an outlet opening  178  is in fluid communication with the outlet conduit  160 . 
     The ampoule further comprises the bottom wall  140  having a top surface  142 . From the top surface  142  extend a plurality of concentric elongate walls  150 , each of the concentric elongate walls  150  comprising a plurality of openings  152  offset from openings  152  of one or more adjacent walls  150  of the plurality of elongate walls  150 . In some embodiments, each of the plurality of concentric elongate walls  150  comprise a plurality of openings  152 . In some embodiments, each of the plurality of concentric elongate walls  150  comprise a single opening  152 . As shown in  FIG.  4   , the openings  152  of the plurality of concentric elongate walls  150  are offset from one another allow gas to flow through into a subsequent flow channel of an adjacent concentric elongate walls  150  creating a torturous path. In some embodiments, each opening  152  of each of the plurality of concentric elongate walls  150  are offset by 180 degrees by one another. 
     The ampoule  100  further comprises a lid  170  having a bottom surface  172  in contact with one or more of the outer cylindrical wall  110 , the inner cylindrical wall  120  or an outlet conduit  160  to enclose the inlet channel  130  and the precursor cavity  102 . 
     In some embodiments, the bottom surface of the lid  170  is integral with the outlet conduit  160 . In some embodiments, the bottom surface of the lid  170  is integral with the inner cylindrical wall  120  and the outlet conduit  160 . In such configurations, the inner cylindrical wall  120  and outlet conduit  160  can also be integral with a top wall  126 , thus connecting the inner cylindrical wall  120 , the outlet conduit  160  and the top wall  126  with the bottom surface of the lid  170 . In further embodiments, the inner cylindrical wall and the outlet conduit  160  are integral with the top wall  126  forming a manifold which can be used with conventional lids. Said manifold comprising the inner cylindrical wall  120  and the outlet conduit  160  can be removed, serviced and refilled with precursor within the precursor cavity  102  formed by the inner surface  122  of the inner cylindrical wall  120 . 
     As previously described, in some embodiments, the outer cylindrical wall  110  is integral with the bottom wall  140 . In some embodiments, as shown in  FIG.  3   , the outer cylindrical wall  110  is removably secured to the top surface  142  of the bottom wall  140  by a plurality of fasteners  144  such that the precursor cavity  102  can be accessible and services from the bottom. The top surface  142  of the bottom wall  140  can further include a channel  146  for an O-ring to create a fluid-tight seal between the top surface  142  of the bottom wall  140  and a bottom surface of the inner cylindrical wall  120 . 
     In embodiments where the outer cylindrical wall  110  is a separate component from the lid  170 , a flange  116  can extend outward from the outside surface  114  and from a top surface  118  of the outer cylindrical wall  110 , the flange  116  in contact with the bottom surface of the lid  170 . In such embodiments, the top surface  118  can further include a groove or channel  119  for an O-ring to create a fluid-tight seal between the top surface  118  the bottom surface of the lid  170 . The lid  170  can be secured to the flange  116  by a plurality of fasteners  117  extending through the flange  116 . 
     The lid  170  further includes an inlet opening  176  in fluid communication with the inlet channel  130  and an outlet opening  178  in fluid communication with the outlet conduit  160 . As shown in  FIG.  2   , the outlet conduit  160  has an inside surface and an outside surface with the outside defining an outer diameter R ODO  which is less than the inner diameter RID of the inner cylindrical wall  120 , and an inner diameter defining an outlet channel  168  of the outlet conduit  160 . The bottom surface  172  of the lid  170  is in contact with one or more of the outer cylindrical wall  110 , the inner cylindrical wall  120  or the outlet conduit  160  to enclose the inlet channel  130  and the precursor cavity  102 , with the precursor cavity  102  being defined by the inner surface  122  of the inner cylindrical wall  120 . 
     The  102  is enclosed by a filter media  180  in contact with a bottom end  127  of the inner cylindrical wall  120 . As best shown in  FIG.  1   , the bottom end  127  can include a notch for nesting with the filter media  180 . In some embodiments, the bottom end  127  further includes an inner sloped flange  128 . In some embodiments, the filter media  180  is secured between an outer retention ring  182  and the bottom end  127  of the inner cylindrical wall  120 , and the outer retention ring  182  can be fastened to the bottom end  127  of the inner cylindrical wall  120  by a plurality of fasteners. In some embodiments, the outer retention ring  182  can include threads which can thread into corresponding threads located on the bottom end  127  of the inner cylindrical wall  120 . In some embodiments, the outer retention ring  182  can be fastened or secured to the bottom end  127  of the inner cylindrical wall  120  by a compression fit or a snap-fit or with the use of a c-clip. In some embodiments, the filter media  180  is secured between an inner retention  184  ring and a bottom surface of the outlet conduit  160 . 
     The filter media  180  in the form of a planar disk and is concentric to the outlet conduit  160 . The filter media  180  has a porosity such that vaporized precursor may pass through but liquid or solid precursor may not. In some embodiments, the filter media  180  has a porosity in the range of 0.2 to 2000 microns. 
     The filter media  180  is in contact with a top surface of each of the plurality of concentric elongate walls  150  defining a gas exchange zone  104 . The gas exchange zone  104  is formed between the filter media  180 , the plurality of concentric elongate walls  150  and the bottom wall  140 , the gas exchange zone  104  forming a torturous path for a gas to flow from the inlet channel  130  to the outlet conduit  160 . Solid precursor rests above the filter media  180 , such that depletion of solid precursor does not cause concentration variations within the gas exchange zone  104 . 
     Above the top surface of the filter media  180 , low vapor pressure material (referred to as a “precursor” or “precursor material”) is within the precursor cavity  102 , residing above the filter media  180 . Space above the material within the precursor cavity  102  is a dead space of the ampoule  100 . As the material epletes, the volume of the dead space increases without affecting the concentration of the saturated or partially saturated carrier gas within the gas exchange zone  104  due to the volume of the gas exchange zone  104  remaining constant. The material can be a precursor for use with a semiconductor manufacturing process. In one or more embodiments, the material with a low vapor pressure is a solid. 
     As the ampoule  100  is heated, the precursor vaporizes creating a saturated vaporized precursor within the precursor cavity  102 . As explained in further detail below, as carrier gas passes across the filter media  180  within the gas exchange zone  104 , it mixes with vaporized precursor material which has passed through the filter media  180 . Heating the ampoule  100  causes the material in intimate or proximate contact with the filter media  180  to sublime and diffuse across and through the filter media  180 . The sublimed material saturates the carrier gas after passing through the filter media  180 . In some embodiments, the dead space above the precursor material can contain sublimed material in vapor form. 
     Because the material is fed through the filter media  180  in a bottom fed configuration, depletion of material does not cause concentration variations within the gas exchange zone  104 . 
     The inlet opening  176  is generally configured to allow a connection to a gas source by way of suitable piping and valve(s) and may have suitable threaded or sealing connections. In one or more embodiments, the gas source is a carrier gas; in one or more embodiments, the carrier gas is inert, such as N 2 , Ar or He; in one or more embodiments, the carrier gas is not inert, such as H 2 , provided the carrier gas doesn&#39;t react with precursor in vessel. The outlet opening  178  is generally configured to be able to connect to a line, including suitable piping and valve(s), to allow the flow of gases, which may include entrained particles, exiting the ampoule  100  to flow to a processing chamber (or other component). The inlet opening  176  and the outlet opening  178  may have a welded or threaded connection to allow a gas line to be connected. While the embodiments depict one of each an inlet and an outlet port, should a particular application require, multiple inlet ports and outlet ports may be present. 
     The plurality of concentric elongate walls  150  each comprise a plurality of openings  152  forming a torturous flow path signified by the arrows in the figures. The plurality of concentric elongate walls  150  and the plurality of openings  152  together form a maze-like or “zig-zag” torturous flow path such that not one of the plurality of openings  152  overlaps with another plurality of openings. By way of example, gas enters from a plurality of openings  152  of an outermost elongate wall  150   a  and exits from an plurality of openings  152  to an innermost elongate wall  150   b . Stated differently, the plurality of openings  152  of any of the elongate walls  150  is offset from an adjacent elongate wall  150 . In some embodiments, each of the plurality of concentric elongate walls  150  only comprises one opening  152  as shown in  FIG.  4   . 
     In the figures, a flow path is generally indicated by a series of dashed arrows showing the gas source “G” starting from the inlet opening  176  and exiting through the outlet opening  178 . In some embodiments, as best shown in  FIGS.  1 - 2   , the inlet opening  176  and outlet opening  178  are integral to the lid  170 . A flow path is defined as gas first entering from the inlet opening  176  and being flown around the inlet channel  130 . As the gas reaches the bottom wall  140 , the gas enters an outermost opening  152  of the outermost elongate wall  150   a . Upon entry into the outermost opening  152 , the gas proceeds through the gas exchange zone  104  and torturous path formed by the plurality of concentric elongate walls  150  until the gas exists the torturous path by exiting through an innermost opening  152  of the innermost elongate wall  150   b . Vaporized precursor filters through the filter media  180  to mix with the carrier gas as the carrier gas passes through the gas exchange zone  104 . The mixed gasses exit through the outlet conduit  160  and through the outlet opening  178 . 
     In some embodiments, a fine filter media is positioned within the outlet opening  178  such that fine particles and/or droplets of precursor do not exit the ampoule. In some embodiments, the fine filter media may be any suitable material or configuration or dimensions or media grade offering one or more of the following characteristics: withstands long-term exposure to the precursor, does not introduce a pressure drop that would impede effective delivery of the precursor, pore size to inhibit and/or prevent fine particles and/or droplets of precursor from exiting the ampoule to protect outlet equipment, and pliable to be capable of making a slight seal with the cylindrical shaft. A non-limiting, exemplary porosity of the fine filter media may be greater than or equal to 0.1 micrometers to less than 100 micrometers, and all values and subranges therebetween, as measured by average pore size. 
     In some embodiments, the ampoule  100  further comprises one or more external heating elements positioned around the ampoule  100 . In some embodiments, an internal heating element is positioned and in contact with the bottom wall  140 . In some embodiments, a cable heater is positioned and in contact with the bottom wall  140  such that gases flowing within the gas exchange zone  104  are heated, promoting both sublimation of the precursor material and saturation of the carrier gas. The one or more external heating elements are configured to vaporize the material within the precursor cavity  102  and the internal heating element is configured to heat the elongate walls  150  to promote sublimation of the vapor precursor and carrier gas G throughout the gas exchange zone  104 . 
     In some embodiments, each of the aforementioned structures which come into contact with one another further comprise circular channels for the placement of O-rings or other sealants. In particular, in some embodiments, one or more O-rings is positioned between the filter media  180  and outer retention ring  182 , inner retention ring  184 , and inner cylindrical wall  120 . 
     In some embodiments, the ampoule  100  is stored and transported up-side-down such that the material rests on the bottom surface  172  of the lid  170 . In such a configuration, damage to the filter media  180  is prevented, and migration of the material through the filter media  180  is prevented. 
     In some embodiments, components are connected using removable bolts through appropriately shaped openings, which may have a threaded portion to allow for easy connection of a threaded bolt. The bolts can be removed to allow disassembly. 
     According to one or more embodiments, the plurality of openings of any embodiment are suitable to allow carrier gas to flow from one flow channel to another. The plurality of openings may take any suitable shape and/or configuration and/or location along the elongate walls to accommodate flow of entrained and/or saturated carrier gas. Features of the plurality of openings could be a plurality of holes, tapered slots, or other shapes. In one or more embodiments, the plurality of openings are sized and shaped to provide a varying conductance of carrier gas along a longitudinal distance of the container. In one or more embodiments, the plurality of openings opening(s) increase in size in order to increase conductance from the lid toward the bottom wall of the ampoule. 
     In one or more embodiments, the plurality of openings are notches located at a top end of the elongate walls near the lid. In one or more embodiments, each of the plurality of openings spans a longitudinal distance of greater than or equal to 1-5% to less than or equal to 100% of a length of the wall, including all values and subranges therebetween. 
     The degree of saturation of conventional ampoules decreases as the solid precursor is consumed due to an increase in volume of the precursor cavity. However, in the embodiments described, because sublimation occurs in the sublimation cavity, which is separated by filter media, the decrease of solid precursor does not affect the degree of saturation, as the volume of the sublimation cavity remains constant. Furthermore, in conventional ampoules, as the precursor is consumed, the gas flow is adjusted during processing to maintain sufficient ratios. However, in the embodiments described the gas flow can remain constant due to the constant volume of the sublimation cavity. 
     It is understood that the presence of inlet ports, outlet ports and channels/conduits is not limiting and that the number of ports, channels and conduits may be chosen based on space constraints and/or precursor characteristics and/or design need. 
     In some embodiments, the gas flow across the filter media and through the torturous path is sufficient to entrain and/or vaporize and/or sublime the precursor without a need for bubbling. 
     Thermocouples, mass flow meters, and pressure gauges may be included in the equipment denoted herein in order to monitor process conditions. In one or more embodiments, a mass flow meter is provided to monitor gas flow into the inlet port. In one or more embodiments, a thermocouple is installed in the bottom wall of the container and at any of the previously disclosed heater locations. In one or more embodiments, a pressure gauge is provided on the inlet line and/or the outlet line. A pressure range within the ampoule in accordance with some embodiments is greater than or equal to 25 torr to less than or equal to 150 torr. 
     Reference throughout this specification to “one embodiment,” “certain embodiments,” “one or more embodiments” or “an embodiment” means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases such as “in one or more embodiments,” “in certain embodiments,” “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments. 
     Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention include modifications and variations that are within the scope of the appended claims and their equivalents.