Patent Publication Number: US-2015079283-A1

Title: Apparatus and method to deposit doped films

Description:
ACKNOWLEDGEMENT OF GOVERNMENT SUPPORT 
     This disclosure was made with government support under Government Contract No. FA9451-10-C-0273 
    
    
     TECHNICAL FIELD 
     The invention relates to in general, a deposition apparatus and process. 
     BACKGROUND 
     This section introduces aspects that may help facilitate a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is prior art or what is not prior art. 
     Deposition processes to form doped films can include sputtering, pulsed laser ablation, sol-gel deposition, ion exchange or ion implantation. Often, however, these processes are cumbersome and the rate of deposition is very slow, e.g., hours to deposit a film of a few microns in thickness, and therefore these processes are not suitable for industrial production. 
     SUMMARY 
     One embodiment is a deposition apparatus comprising a vaporizer chamber configured to hold a solid precursor of a dopant element therein. Gas input and output lines are connected to the vaporizer chamber and flow rate controllers are coupled to each of the gas input and output lines. The flow rate controllers are configured to adjust a rate of carrier gas flow into and out of the vaporizer chamber through the gas input and output lines. The vaporizer chamber has a temperature controller and pressure controller to produce vapors of the solid precursor in the vaporizer chamber that can be carried with the carrier gas flow through the output line. 
     In some such embodiments, the dopant element of the solid precursor in the vaporizer chamber is a single element type. In any such embodiments, the apparatus can be further configured to allow a passage of the carrier gas flow through a porous frit connected to the end of the gas input line in the vapor chamber. In any such embodiments, the flow rate controllers can be configured to adjust the flow rate of the carrier gas flow into and out of the vaporizer chamber to substantially match a vapor forming rate of the solid precursor of the dopant element in the vapor chamber. 
     Any such embodiments can further include a vaporizer module having a plurality of the vaporizer chambers each configured to hold a different solid precursor of a different dopant element therein. There can be separate pairs of the gas input and output lines connected to each of the vaporizer chambers, and separate pairs of the flow rate controllers coupled to each of the gas input and output lines, wherein the flow rate controllers separately adjust a rate of the carrier gas flow into and out of the each of the vaporizer chambers. Each of the vaporizer chambers can have separately controllable temperature controllers and pressure controllers to produce vapors of each of the different solid precursors in each of the vaporizer chambers to thereby produce different vapors of the precursors of the dopant elements that can be carried with the carrier gas through the output lines. In some such embodiments, one of the vapor chambers can hold the solid precursor of the dopant element of aluminum and another one of the vapor chambers holds the solid precursor of the dopant element of a rare earth element. In some such embodiments, one of the vapor chambers can hold the solid precursor of the dopant element of ytterbium and another one of the vapor chambers holds the solid precursor of the dopant element of a rare earth element other than ytterbium. 
     Any such embodiment can further including a reactor assembly located inside of a deposition chamber of the apparatus, the reactor assembly receiving as a first input the vapor forms of the precursors of the dopant elements transported from the output line. In some such embodiments, the reactor assembly can be further configured to receives as a second input having vapor forms of precursor gases for a doped film to be formed in the deposition chamber. In some such embodiments, the reactor assembly can be configured to receive different vapor precursors of different types of the dopant elements separately formed in different ones of the vaporizer chambers. In some such embodiments, the reactor assembly can be configured to receives as the first input, the vapor forms of the precursors of the dopant elements of a rare earth element and one of aluminum and ytterbium, and as the second input, a gas precursor for the doped film. 
     Another embodiment is a method comprising generating a vapor form of a solid precursor of a dopant element. The solid precursor of the dopant element is placed into a vaporizer chamber. Gas input and output lines are connected to the vaporizer chamber and flow rate controllers are coupled to each of the gas input and output lines. A temperature and pressure inside of the vaporizer chamber is controlled to produce the vapor form of the solid precursor of the dopant element. A flow rate of carrier gas into and out of the vaporizer chamber is adjusted through the gas input and output lines to carry the vapor form of the solid precursor of the dopant element through of the output line. 
     In some such embodiments, adjusting the flow rate of the carrier gas flow into and out of the vaporizer chamber substantially matches a forming rate of the vapors of the solid precursor of the dopant element in the vaporizer chamber. 
     Any such embodiments can further include generating a vapor form of a second solid precursor of a second dopant element including. Generating the vapor form can include placing the second solid precursor of the second dopant element into a second vaporizer chamber, wherein second gas input and output lines are connected to the second vaporizer chamber and second flow rate controllers are coupled to each of the second gas input and output lines. Generating the vapor form can include controlling a temperature and pressure inside of the second vaporizer chamber to produce a vapor of the second vapor form of the solid precursor of the second dopant element. Generating the vapor form can include adjusting a flow rate of the carrier gas into and out of the second vaporizer chamber through the second gas input and output lines to carry the vapor form of the second solid precursor of the second dopant element through of the second output line. 
     In some such embodiments, adjusting the flow rate of the carrier gas flow into and out of the second vaporizer chamber substantially matches a forming rate of the vapors of the second solid precursor of the second dopant element in the second vaporizer chamber. In some such embodiments, the vapor form of the solid precursor, and the vapor form of the second solid precursor, can be simultaneously delivered through the first and second outline lines, respectively, to a common line connected to a deposition chamber. In some such embodiments, the vapor form of the solid precursor, and the vapor form of the second solid precursor, can be alternately delivered through the first and second outline lines, respectively, to a common input line connected to a deposition chamber of the apparatus. 
     Any such embodiments, can further include forming a doped film on a substrate, including delivering the vapor form of the solid precursor of the dopant element to a reactor assembly located inside of a deposition chamber. In some such embodiments, forming the doped film further can include delivering a film deposition gases of the doped film to the reactor assembly concurrently with the delivery of the vapor form of the solid precursor of the dopant element. In some such embodiments, forming the doped film further includes simultaneously delivering vapor forms of the solid precursors of different types of the dopant elements, which are separately formed in different vaporizer chambers, to the reactor assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments of the disclosure are best understood from the following detailed description, when read with the accompanying figures. Some features in the figures may be described as, for example, “top,” “bottom,” “vertical” or “lateral” for convenience in referring to those features. Such descriptions do not limit the orientation of such features with respect to the natural horizon or gravity. Various features may not be drawn to scale and may be arbitrarily increased or reduced in size for clarity of discussion. Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  presents a block diagram of an apparatus; and 
         FIG. 2  presents a flow diagram of a method of use such as a method of using any of the apparatuses described in the context of  FIG. 1 . 
     
    
    
     In the Figures and text, similar or like reference symbols indicate elements with similar or the same functions and/or structures. 
     In the Figures, the relative dimensions of some features may be exaggerated to more clearly illustrate one or more of the structures or features therein. 
     Herein, various embodiments are described more fully by the Figures and the Detailed Description. Nevertheless, the inventions may be embodied in various forms and are not limited to the embodiments described in the Figures and Detailed Description of Illustrative Embodiments. 
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The description and drawings merely illustrate the principles of the inventions. It will thus be appreciated that a person of ordinary skill in the relevant arts will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the inventions and are included within its scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the inventions and concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the inventions, as well as specific examples thereof, are intended to encompass equivalents thereof. Additionally, the term, “or,” as used herein, refers to a non-exclusive or, unless otherwise indicated. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. 
     Described herein is an apparatus and process to facilitate deposition processes to form doped films. In some cases the film can be an optical quality film used as a component part of planar lightwave circuits (PLCs). In some embodiments, the apparatus and processes described herein can facilitate the formation of aluminum doped films, rare earth element doped films, or combinations of aluminum and rare earth element doped films. The use of aluminum as a co-deposited modifier for the rare earth element doped films can advantageous allow for higher concentrations of active rare earth element doping in the film and facilitate producing a broad emission spectrum from the doped film. 
     The deposition process and apparatus further described below can facilitate the formation of uniform and constant concentration of the rare earth element and/or aluminum across the thickness of the doped film having a thickness of several microns in shorter periods (e.g., minutes) than certain other types of deposition processes. 
     One embodiment is a deposition apparatus.  FIG. 1  presents a block diagram of an apparatus  100 . 
     In some embodiments, the deposition apparatus  100  can be or include chemical vapor deposition (CVD apparatus, such as a plasma enhanced chemical vapor deposition (PECVD) apparatus, or a metal organic chemical vapor deposition (MOCVD) apparatus. One of ordinary skill in the pertinent arts would understand from this disclosure how to make and use other embodiments of the deposition apparatus. 
     As illustrated for the embodiment shown in  FIG. 1 , the apparatus  100  comprises a vaporizer chamber  105  configured to hold a solid precursor  107  of a dopant element therein. The apparatus  100  also comprises gas input and output lines  110 ,  112  connected to the vaporizer chamber  105 . The apparatus  100  also comprises flow rate controllers  115 ,  117 , e.g., on/off valve and needle valves, respectively, in some embodiments. The flow rate controllers, configured as input and output flow rate controllers  115 ,  117 , respectively, can be coupled to each of the gas input and output lines  110 ,  112 . The flow rate controllers  115 ,  117  are configured to adjust a rate of carrier gas flow  120  into and out of the vaporizer chamber through the gas input and output lines  110 ,  112 . The vaporizer chamber  105  has a temperature controller  121  and pressure controller  122  to produce vapors of the solid precursor  127  in the vaporizer chamber  105  that can be carried with the carrier gas flow  120  (e.g., helium or other inert gases) through the output line  112 . As illustrated, in some embodiments the carrier gas  120  is transferred to the input line  110  via a common input line  124  having its own flow controller  125 . 
     The temperature controller  121  can include a temperature monitor and heater and the pressure controller  122 , can include a pressure monitor, to facilitate producing a combination of increased temperature and pressure inside of the vaporizer chamber  105 . In some embodiments, depending on the type of solid precursor  107  used, the production of the vapors  127  of the solid precursor  107  can be formed via direct sublimation of the solid precursor  107 , while in other embodiments, vapors  127  of the solid precursor  107  can be formed via vaporization of a liquid state of the solid precursor  107 . Advantages of using a solid precursor of aluminum, or of rare earth elements, include avoiding the need to handle toxic and/or explosive liquid forms of precursors of such elements. In some embodiments the vapors  127  of the solid precursor  107 , including aluminum solid precursors can be formed at relatively low temperatures (e.g., about 700° C. or less) compared to certain other deposition processes. 
     Examples ligand of the solid precursor  107  include metal beta-diketonate ligand complexes such as tris(2,2,6,6-tetramethyl-3,5-heptanedionato) (TMHD) rare earth element ion (III) or aluminum ion (III) complexes. Non-limiting examples include Yb(TMHD) 3 , Er(TMHD) 3 , Ho(TMHD) 3 , Tm(TMHD) 3 , or Al(TMHD) 3 . Other examples of the solid precursor include metal fluorobeta-diketonate ligand complexes such as Tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) (FOD) rare earth element ion (III) or aluminum ion (III) complexes. Non-limiting examples include Yb(FOD) 3 , Er(FOD) 3 , or Al(FOD) 3 . Other examples of the solid precursor include metal metallocene ligand complexes such rare earth element ion (III) or aluminum ion (III) metallocene complexes. Non-limiting examples include Tris(i-propylcyclopentadienyl) Er. Other examples of the solid precursor include the aluminum(III) acetylacetonate ligand complex (Al(acac) 3 ). One skilled in the pertinent arts would understand that other types of ligands could be used to form the solid precursor. 
     In some embodiments, the dopant element of the solid precursor  107  placed in the vaporizer chamber  105  is a single metal element type, for example aluminum only, or, a single rare earth element type only. Using a single metal element type in the chamber  105 , or a different metal element type in each of multiple different chambers, provides the advantage of allowing precise control of the conditions to form uniform amounts of the vapors of the solid precursor  127 . This can be advantageous when the solid precursors of different elements have widely different melting points and sublimation pressures or vaporization pressures. In some embodiments, however, there can be multiple different solid precursors  107  of different dopant elements in a single chamber  105 . 
     Similarly, in some embodiments, the dopant element of the solid precursor  107  placed in the vaporizer chamber  105  is a single ligand type, for example only TMHD, only FOD, only metallocene or only acac. Using a single ligand type in the chamber  105 , provides the advantage of allowing precise control of the conditions to form uniform amounts of the vapors of the solid precursor  127 . In some embodiments, however, there can be multiple different solid precursors  107  of different ligand types in a single chamber  105 . 
     In some embodiments, the solid precursor  107  placed in the vaporizer chamber  105  has a single ligand type and a single dopant element type. For instance, in some embodiments the single solid precursor  107  type can be Al(acac) 3 . Aluminum doped semiconductors can increase the electrical conductivity of certain doped films, such as aluminum doped GaN- or GsAs-films used in electrical semiconductor transistors. For instance, in some embodiments, the single solid precursor  107  type can be one of Er(TMHD) 3 , Ho(TMHD) 3 , or Tm(TMHD) 3 . Such rare earth element doped films can improve light emission from active optical device components in photonic integrated circuit such as diodes, lasers or light amplifiers or other active device components familiar to those skilled in the pertinent art. 
     As further illustrated in  FIG. 1 , in some embodiments, the carrier gas flow  120  passes through a porous frit  130  (e.g., a porous metal, glass or ceramic frit) connected to an end  135  of the gas input line  110  in the vapor chamber  105 . Passing the carrier gas through the porous frit  130  can facilitate uniform mixing of the vapors of the solid precursor  127  into the carrier gas stream exiting the chamber  105  through the output line  112 . 
     In some embodiments, it is desirable to provide a uniform concentration of the vapor form  127  of the solid precursor  107  in the outlet line  112 . Having a uniform concentration of the vapor form  127  in the outlet line  112 , in turn, can facilitate forming a doped film with a uniform concentration of the dopant element throughout the entire thickness of the film. To provide the uniform concentration of the vapor form  127  in the outlet line  112  the flow rate controllers  115 ,  117  (e.g., via precision valves) can adjust the flow rate of the carrier gas flow into and out of the vaporizer chamber  105  to substantially match a vapor  127  forming rate of the solid precursor  107  of the dopant element in the vaporizer chamber  105 . That is, for a given temperature and pressure in the chamber  105  that produces vapors of the solid the precursor  127 , the flow rate of the carrier gas flow  120  into and out of the vaporizer chamber  105  is adjusted to value that removes the vapor  127  from the chamber at a same rate, e.g., within about 10 percent and in some embodiments within about 1 percent, that the vapor form  127  of the solid precursor  107  is being produced at. One skilled in the pertinent art would understand how in a calibration process, a doped film could be analyzed to measure the distribution of dopant concentrations therein, and then adjust the flow rate controllers  115 ,  117  accordingly to provide the desired uniformity of dopant in the film. 
     As also illustrated in  FIG. 1 , some embodiments the apparatus  100  further include a vaporizer module  140  having a plurality of the vaporizer chambers (e.g., chambers  105 ,  142 ) each chamber configured to hold a different solid precursor of a different dopant elements  107 ,  145  therein. For example, Er(TMHD) 3  can be the solid precursor  107  in one chamber  105  and Al(acac) 3  can be the solid precursor  145  in another chamber  142 ). 
     For some such embodiments, separate pairs of the gas input and output lines are connected to each of the vaporizer chambers  105 ,  142  (e.g., first input and output lines  110 ,  112  and second input and output lines  144 ,  146 , respectively). 
     For some such embodiments, separate pairs of the flow rate controllers (e.g., first controllers  115 ,  117  and second controllers  150 ,  152 ) are coupled to each of the gas input and output lines (e.g., lines  110 ,  112  and  144 ,  146 , respectively). The flow rate controllers  115 ,  117 ,  150 ,  152  can be configured to separately adjust a rate of the carrier gas flow  120  into and out of the each of the vaporizer chambers  105 ,  142 , e.g., to match distinct vapor forming rates from different solid precursors  107 ,  145  in each chamber  105 ,  142 . 
     For some such embodiments, each of the vaporizer chambers  105 ,  142  have separately controllable temperature controllers and pressure controllers (e.g., temperature and pressure controllers  121 ,  122  and  154 ,  156 , respectively) to produce vapors  127 ,  157  of each of the different solid precursors  107 ,  145  in each of the vaporizer chambers  107 ,  142 . The separately produced vapors  127 ,  157  can be carried with the carrier gas  120  through the output lines  112 ,  146  of the chambers  105 ,  142 . 
     Because each vaporizer chamber  105 ,  142  can have its own temperature, pressure and flow controllers, the individual amount and the ratios of the various elements deposited in the doped film can be precisely controlled. 
     In some embodiments, two or more vaporizer chambers  105 ,  142  of the module  140  are used concurrently to simultaneously deposit different dopant elements present in each of chambers. 
     For instance, in some embodiments, one of the vapor chambers (e.g., chamber  105 ) can hold the solid precursor  107  of the dopant element of aluminum (e.g., Al(acac) 3 ), and, another one of the vapor chambers (e.g., chamber  142 ) can hold the solid precursor  145  of the dopant element of a rare earth element (e.g., a rare element complex with one of (TMHD) 3 , FOD, or metallocene) ligands. Vapors of solid precursor of these dopant elements  127 ,  157  can be simultaneously carried with the carrier gas flow  120  through the output lines  112 ,  146 , respectively. The inclusion of aluminum can facilitate having a higher concentration of active rare earth dopant in doped films, and, facilitate a broad emission spectrum generated in the doped film. 
     A simultaneous deposition of vapors of both aluminum and rare element dopants (e.g., vapors  127 ,  157 ) promotes having uniform and constant concentrations of the dopants through the entire thickness of the film. In some embodiments, a combined flow of the vapors  127 ,  157  of solid precursors of these dopant elements has an atomic ratio of aluminum to the individual different types of rare earth elements of at least about 3:1, and in some embodiments, an atomic ratio of aluminum to rare earth elements in a range of about 5:1 to 20:1. For instance, such atomic ratios of aluminum to rare earth elements can be present in a combined output line  160  that combines the output lines (e.g., lines  112 ,  146 ) from all of the chambers  105 ,  142  of the apparatus  100 . Such atomic ratios of aluminum to rare earth elements can be delivered to the doped film to be formed. As illustrated the combined line  160  can have its own separate flow rate controller  161 . 
     For instance, in some embodiments, one vaporizer chamber  105  can hold the solid precursor  107  of the dopant element of ytterbium (e.g., Yb(TMHD) 3 ), and, another one of the vaporizer chambers  142  can hold the solid precursor  145  of the dopant element of a rare earth element other than ytterbium (e.g., Er(TMHD) 3 ). The inclusion of ytterbium can facilitate enhanced light emission rare earth dopants in doped film, such as light emission from erbium doped films in the 1.5 micron wavelength range. For instance, in some embodiments, one chamber  107  can hold the solid precursor  107  of the dopant element of holmium (e.g., Ho(TMHD) 3 ), and, another one of the chambers  142  can hold the solid precursor  145  of the dopant element of a rare earth element of thulium (e.g., Tm(TMHD) 3 ). The combination of holmium and thulium in the doped film can facilitate the formation of a light emission band in the 2 micron wavelength range. 
     One skilled in the pertinent arts would appreciate how similar processes can be used to simultaneously deposit multiple different dopant elements in the doped film. 
     In some embodiments, however, only one vaporizer chamber (e.g., one of chambers  107  or  142 ) is operated at a time to sequentially deposit different dopants from each of the chambers. For instance, a doped film can be formed using the apparatus  100  such that different type of rare element elements or other dopants are present at different regions through the thickness of the film. 
     As further illustrated in  FIG. 1 , in some embodiments, the apparatus  100  can further include other components, e.g., components of a CVD apparatus. Such components can include a deposition chamber  162 , heating module  164 , and gas delivery system  166  to control the inlet and outlet of deposition materials into and out of the deposition chamber  162 . 
     In some embodiments, a combined output line  160 , that combines the output lines  112 ,  146 , from all of the vaporizer chambers  105 ,  142  can be an input line connected to the gas delivery system  166 , or in other cases directly connected to the deposition chamber  162 . As illustrated, a separate delivery line  170  can be configured to deliver film deposition gases  172  to the gas delivery system  166  or in other cases directly connected to the deposition chamber  162 . Non-limiting examples of the film deposition gases  172  include tetraethoxysilane (TEOS), silane (SiH 4 ), germane (GeH 4 ) and phosphine (PH 3 ). 
     Some embodiments of the apparatus  100  can further include a radio-frequency power source  174  used to generate a plasma inside of a reactor assembly  176  located inside of the deposition chamber  162 . The reactor assembly  176  can be configured to receive as a first input the vapor forms of the precursors of the dopant elements (e.g., precursors vapors  127 ,  157 ) transported from the combined output line  160  (or single output line  112 , in some embodiments). 
     The reactor assembly  176  can be further configured to receive as a second input, the film deposition gases  172  for a doped film  190  to be formed in the deposition chamber  162 . In some embodiments, the film deposition gases  172  can be separately delivered to the reactor assembly  176  via separate delivery line  170 . In other embodiments the film deposition gases  172  can be delivered via a gas delivery system  166  which in turn receives both of the vapor forms of the precursors of the dopant elements  127 ,  157 , and, the film deposition gases  172  and then delivers the vapors  127 ,  157 , and gases  172  to the reactor assembly  176  via a separate inlet line  178 . 
     A control module  180  (e.g., a computer) of the apparatus  100  can be configured to control the flow of deposition material, and/or, the deposition chamber&#39;s pressure and temperature and/or the deposition substrate&#39;s temperature. 
     In some embodiments, the reactor assembly  176  can be controlled to receive, e.g., along with the film deposition gases  172 , different vapor precursors of different types of the dopant elements (e.g., vapors  127 ,  157 ) separately formed in different vaporizer chambers (e.g., chambers  105 ,  142  of the vaporizer module  140 ). For instance, in some embodiments, the reactor assembly  176  receives as the first input, the vapor forms of the precursors of the dopant elements of a rare earth element and one of aluminum and ytterbium, and as the second input, a gas precursor of tetraethoxysilane (TEOS) or SiH 4 , for the doped film  190 . 
     Another embodiment is a method, e.g., a method of forming a doped film.  FIG. 2  presents a flow diagram of an example method  200 , such as implemented by any of the apparatuses  100  described in the context of  FIG. 1 . With continuing reference to  FIG. 1 , the method comprises a step  205  of generating a vapor form  127  of a solid precursor of a dopant element  107 . 
     Generating the vapor form  127  in step  205  includes a step  210  of placing the solid precursor  107  of the dopant element into a vaporizer chamber  105 , wherein gas input and output lines  110 ,  112  are connected to the vaporizer chamber  105  and flow rate controllers  115 ,  117  are coupled to each of the gas input and output lines  110 ,  112 . 
     Generating the vapor form  127  in step  205  also includes a step  215  of controlling a temperature and pressure inside of the vaporizer chamber  105  (e.g., via temperature and pressure controllers  121 ,  122 ) to produce the vapor form  127  of the solid precursor  107 . Generating the vapor form  127  in step  205  further includes a step  220  of adjusting a flow rate of carrier gas  120  flow into and out of the vaporizer chamber  105  through the gas input and output lines to carry the vapor form  127  through the output line  112 . 
     In some embodiments, as part of adjusting step  220 , the carrier gas flow  120  into and out of the vaporizer chamber  105  substantially matches a vapor forming rate of the vapors of the solid precursor of the dopant element  127  in the chamber  105 . For instance, if the vapor form  127  were being generated at a rate of 100 arbitrary volume units per minute, then the carrier gas flow  120  into and out of the vaporizer chamber  105  is adjusted to a flow rate of 100 volume units per minute within ±10 percent in some embodiments, within ±1 percent. 
     Some embodiments of the method  200  further include a step  230  of generating a vapor form  157  of a second solid precursor of a second dopant element  145 . Generating the second vapor form  157  in step  230  can include a step  232  of placing the second solid precursor of the second dopant element  145  into a second vaporizer chamber  142 . Second gas input and output lines  144 ,  146  are connected to the second vaporizer chamber  142  and second flow rate controllers are coupled to each of the second gas input and output lines  144 ,  146 . Generating the second vapor form  157  in step  230  can also include a step  234  of controlling a temperature and pressure inside of the second vaporizer chamber  142  to produce the second vapor  157  in the second vaporizer chamber  142 . Generating the second vapor form  157  in step  230  can further include a step  236  of adjusting a flow rate of the carrier gas  120  into and out of the second vaporizer chamber  142  through the second gas input and output lines  144 ,  146  to carry the second vapor form  157  through the second output line  146 . As part of the adjusting step  236  the flow rate of the carrier gas flow  120  into and out of the second vaporizer chamber  142  substantially matches a forming rate of the vapors of the second solid precursor of the second dopant element  157  in the chamber  142 . 
     In some embodiments of the method  200 , the vapor form  127  of the solid precursor  107 , and the vapor form  157  of the second solid precursor  145 , are simultaneously delivered in step  240  through the first and second outline lines  112 ,  146 , respectively, to a gas line  160  (e.g., a combined or common line  160  in some embodiments) connected to a deposition chamber  162 . 
     In other embodiments of the method  200 , the vapor form of the solid precursor  127 , and the vapor form of the second solid precursor  157 , are alternately delivered in step  245 ,  247  through the first and second outline lines  117 ,  146 , respectively, to a line  160  connected to a deposition chamber  162 . 
     Some embodiments of the method  200  further include a step  250  of forming a doped film  190  on a substrate  192 . In some embodiment the doped film has thickness  194  in a range of 1 to 7 microns. Forming the doped film  190  in step  250  can include a step  252  of delivering the vapor form  127  of the solid precursor of the dopant element  107  to a reactor assembly  176  located inside of the deposition chamber  162 . 
     In some embodiments, forming the doped film  190  (step  250 ) can include a step  254  of delivering film deposition gases  172  of the doped film  190  to the reactor assembly  176  concurrently with the delivery of the vapor form  127  (or forms  127 ,  157 ) of the solid precursor  107  (or precursors ( 107 ,  145 ). 
     In some embodiments, forming the doped film  190  (step  250 ) can include simultaneously delivering vapor forms  127 ,  157  of the solid precursors of different types of the dopant elements  107 ,  145 , which are separately formed in different vaporizer chambers  105 ,  142 , to the reactor assembly  176 . 
     Some embodiments of the method  200  further include a step  260  of including patterning the doped film  190  to form one or more active device components (e.g., diodes, lasers or light amplifiers) of a planar lightwave circuit. One skilled in the pertinent arts would be familiar with lithographic and etching processes to pattern the film in accordance with step  260 . 
     Although the present disclosure has been described in detail, a person of ordinary skill in the relevant arts should understand that they can make various changes, substitutions and alterations herein without departing from the scope of the invention.