Classifications

• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B19/00—Liquid-phase epitaxial-layer growth
  • C30B19/06—Reaction chambers; Boats for supporting the melt; Substrate holders
  • C30B19/063—Sliding boat system
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B19/00—Liquid-phase epitaxial-layer growth
  • C30B19/02—Liquid-phase epitaxial-layer growth using molten solvents, e.g. flux
  • C30B19/04—Liquid-phase epitaxial-layer growth using molten solvents, e.g. flux the solvent being a component of the crystal composition
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
  • C30B29/10—Inorganic compounds or compositions
  • C30B29/46—Sulfur-, selenium- or tellurium-containing compounds
  • C30B29/48—AIIBVI compounds wherein A is Zn, Cd or Hg, and B is S, Se or Te

Definitions

• the invention relates to an epitaxy basket intended for the deposition of a layer of CdHgTe by liquid phase epitaxy on a heterosubstrate. It also relates to a method of depositing a layer of CdHgTe on a heterosubstrate using this nacelle
• This invention finds applications in the production of infrared radiation detectors.
• Patent application FR-A-2 736 210 proposes replacing a homosubstrate of this type with a more mechanically robust substrate.
• this document describes a heterosubstrate comprising a basic Ge or Si substrate and an active layer of CdHgTe in which the components are made.
• the CdHgTe layer is deposited by liquid phase epitaxy on the base substrate, through one or more transition layers made of binary, ternary or quaternary II - VI material.
• the epitaxy solution when the epitaxy solution is brought into contact with the heterosubstrate covered with its adaptation layer in CdTe, a dissolution of the heterosubstrate (CdTe / Ge) appears on the input edge of the substrate. .
• the substrate is generally insufficiently covered with CdTe and the epitaxy solution can infiltrate along the edge of the substrate; the latter can then dissolve; however, the solubility of germanium in the tellurium solvent is such that in a few minutes, several hundred milligrams of germanium pass into the solution, which starts the substrate and gives it a "nibbled" appearance.
• the tellurium solution is then contaminated with germanium atoms; the latter also contaminate the layer of CdHgTe in the course of growth, which modifies the electrical properties of the CdHgTe material and causes malfunctions of the detectors thus produced.
• the object of the invention is precisely to remedy the drawbacks of the technique of growth by epitaxy in the liquid phase on a heterosubstrate, described above.
• This nacelle has two horizontal drawers which are moved relative to each other so as to bring the tellurium solution above a chosen area of the heterosubstrate, avoiding that the entry edge of the heterosubstrate is not in contact with the tellurium solution.
• the invention relates to an epitaxy basket for depositing a layer of CdHgTe by liquid phase epitaxy on a heterosubstrate, comprising a first drawer horizontal on which the heterosubstrate to be covered is placed.
• This nacelle is characterized by the fact that it also includes: - a tank capable of containing an epitaxy solution; a well intended to receive this epitaxy solution at the time of the epitaxy of the layer of CdHgTe and having lateral dimensions smaller than those of the heterosubstrate and a space
• the invention also relates to a method of depositing a layer of CdHgTe by liquid phase epitaxy on a heterosubstrate, using the nacelle described above.
• This process is characterized by the fact that it consists: during a pre-epitaxy phase, of introducing an epitaxy solution into the reservoir and of positioning the heterosubstrate on the first drawer; at the start of an epitaxy phase, to move the first drawer to bring the heterosubstrate under the well, then to move the second drawer so as to bring the orifice of this second drawer under the tank and above the well so that the solution flows from the reservoir to the well; - at the end of the epitaxy phase, move the first drawer to separate the heterosubstrate from the epitaxy solution.
• the epitaxy solution can be of the low surface tension type and the heterosubstrate can be of the non-inert type.
• the heterosubstrate used in this process is faceted by a triangular pattern which increases the confinement of the solution on the heterosubstrate.
• FIG. 1 represents the epitaxy nacelle of the invention during the pre-epitaxy phase
• FIG. 2 shows this epitaxy pod at the start of the epitaxy phase
• FIG. 3 represents the epitaxy nacelle during the epitaxy phase
• FIG. 4 represents the epitaxy nacelle in the post-epitaxy phase.
• FIG. 1 shows the epitaxy nacelle according to the invention.
• This nacelle 1 comprises a first horizontal drawer 2 on which is placed the heterosubstrate 3 intended to be epitaxy. It further comprises a second horizontal drawer 4 located above the first drawer 2. Between the two drawers, the nacelle includes a well 6 intended to receive a solution ensuring the epitaxy of the heterosubstrate. This solution called
• epi solution is, for example, a tellurium solvent containing Cd and Hg.
• the lateral dimensions of the well are chosen so as to be smaller than those of the heterosubstrate; one can thus avoid the contact of the epitaxy solution with the edges of the heterosubstrate, and perfectly delimit the zone of the heterosubstrate to be epitaxied.
• the nacelle 1 further comprises a reservoir 5 into which the epitaxy solution is loaded during the pre-epitaxial phase.
• This reservoir 5 is placed vertically from the well 6; the well 6 and the reservoir 5 are separated from each other by the second drawer 4.
• An orifice 7 made in the second drawer 4 ensures the passage of the epitaxy solution from the reservoir 5 towards the well 6 at the start of the epitaxial phase, when the second drawer is positioned so that its orifice 7 is located between the well and the reservoir.
• the space 6b between the surface of the heterosubstrate and the lower edges of the walls 6a of the well 6 is less than or equal to 50 ⁇ m; this makes it possible to increase the confinement of the solution in the well and to limit the risks of infiltration of the solution by capillarity towards the edges of the heterosubstrate. Such a well 6 therefore makes it possible to avoid any contacting of the edges of the heterosubstrate with the epitaxy solution.
• the faceted pattern on the layer of CdTe (or CdZnTe), characteristic of growth by MOCVD (vapor phase growth from organometallics) on the plane of the base substrate is triangular because the growth of CdTe
• Such an epitaxy basket has the further advantage of allowing epitaxy on heterosubstrates which are non-inert with respect to the epitaxy solution, for example heterosubstrates in Germanium or in Silicon.
• FIG. 1 shows the epitaxy nacelle of the invention in the pre-epitaxial phase. During this pre-epitaxy phase, the heterosubstrate to be treated is placed on the first drawer 2 and placed in the standby position; the epitaxy solution is introduced into the reservoir 5.
• Figure 2 shows this epitaxy basket at the start of the epitaxy phase. At this time, the drawer 2 is pushed so as to bring the heterosubstrate to be treated under the well 6 which, at this instant, is empty.
• FIG. 3 shows the step where the epitaxy solution is brought into the well, after the second drawer 4 has been moved so that its orifice 7 is aligned with the reservoir 5 and the well 6.
• the solution d epitaxy then passes into well 6 and epitaxy on heterosubstrate 3 can be performed.
• FIG. 4 shows the epitaxy nacelle 1 in the post-epitaxial phase, that is to say when the heterosubstrate has been epitaxied and it is separated from the epitaxy solution by moving the first drawer 2
• the heterosubstrate epitaxy is referenced 3 'in this figure 4.
• the clearance between the surface of the heterosubstrate and the lower edges of the walls of the well is minimized, which makes it possible, in addition to confining the solution in the well, to limit the risk that a drop of solution remains randomly attached to the surface of the CdHgTe layer when the heterosubstrate is separated from the epitaxy solution.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Crystallography & Structural Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Light Receiving Elements (AREA)
• Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=9507060

Family Applications (1)

Country Status (3)

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Family Cites Families (4)

• 1997
  • 1997-05-21 FR FR9706175A patent/FR2763608B1/fr not_active Expired - Lifetime
• 1998
  • 1998-05-20 EP EP98925759A patent/EP0983395A1/de not_active Withdrawn
  • 1998-05-20 WO PCT/FR1998/001013 patent/WO1998053123A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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