FR2848334A1 - Multi-layer structure production of semiconductor materials with different mesh parameters comprises epitaxy of thin film on support substrate and adhesion on target substrate - Google Patents

Abstract

The production of a multi-layer structure of semiconductor materials comprises: (a) the production of a layer (110) incorporating a superficial thin film on a support substrate (100); (b) the creation of a fragilisation (sic) zone in the assembly (10) formed by the support substrate and the thin film deposited; (c) the adhesion of the assembly with a target substrate (20); (d) the detachment at the level of the fragilisation zone; and (e) the treatment of the surface of the structure thus obtained.

Description

i

  The present invention relates to a method for manufacturing a multilayer structure made of semiconductor materials, said structure comprising a substrate made of a first semiconductor material and a thin surface layer made of a second semiconductor material, the two semiconductor materials having substantially different mesh parameters. .

  Methods of this type are already known.

  It is thus known to produce structures comprising a substrate made of a material such as silicon, and a thin surface layer made of a material such as silicon-germanium (SiGe) or even Germanium (Ge).

  The patent application FR 0208600 in the name of the Applicant thus relates to a method for producing a structure comprising a thin layer of semiconductor material from a wafer comprising a mesh parameter adaptation layer comprising a top layer 15 semiconductor material having a first mesh parameter, characterized in that it comprises the following steps: (a) growing on the upper layer of the matching layer of a semiconductor material film having a second parameter of substantially different nominal mesh size of the first mesh parameter, with a thickness sufficiently small to keep the first mesh parameter of the upper layer of the underlying adaptation layer and thus be constrained, (b) growth on the film of a relaxed layer by semiconductor material having a nominal mesh parameter substantially the same as the first mesh parameter, (c) removing from at least a part of the wafer on the adaptation layer side with respect to the relaxed layer comprising the following operations: formation of an embrittlement zone on the adaptation layer side with respect to the relaxed layer; of energy at the zone of weakening to detach from the wafer a structure comprising the relaxed layer.

  The method of this patent application thus uses a layer transfer technique (in particular SMARTCUTO or ELTRANO type) to form the desired slice.

  And a starting element of this method is a wafer comprising a mesh parameter matching layer, which corresponds to a wafer region having on the surface a substantially relaxed material layer and without a significant number of structural defects, such as dislocations.

  It is specified that the term "relaxed layer" any layer of a semiconductor material which has a non-stressed crystallographic structure, that is to say which has a mesh parameter substantially identical to the nominal mesh parameter of the material of the layer.

  Conversely, the term "stress layer" refers to any layer of a semiconductor material whose crystallographic structure is constrained in tension or in compression during a crystalline growth, such as an epitaxy, requiring at least one parameter of mesh to be significantly different from the nominal mesh parameter of this material.

  The process of the patent application FR 0208600 constitutes an advantageous solution for constituting structures as mentioned at the beginning of this text.

  The object of the present invention is to provide certain additions to the teaching of this patent application.

  In order to achieve this object, the invention proposes a method of manufacturing a multilayer structure made of semiconductor materials, said structure comprising a substrate made of a first semiconductor material and a thin surface layer made of a second semiconductor material, the two semiconductor materials having substantially different mesh parameters, characterized in that the method comprises the following steps: * producing a layer comprising said thin surface layer on a support substrate, * creating an embrittlement zone in the assembly formed by said support substrate and said deposited layer, * bonding said assembly with a target substrate, * detachment at this embrittlement zone, * surface treatment of the structure thus obtained.

  Preferred but nonlimiting aspcets of this process are as follows: a said layer production is made by epitaxy, said epitaxy is carried out with the following steps: stabilization in temperature of the support substrate at a first predetermined stabilized temperature, chemical vapor phase at said first predetermined temperature until a base layer is obtained on the support substrate of a predetermined thickness less than a desired final thickness for said layer comprising the superficial thin layer,> increase of the chemical vapor deposition temperature from the first predetermined temperature to a second predetermined temperature, and> continuing the chemical vapor deposition at said second predetermined temperature until the desired final thickness for the layer is obtained. the first predetermined temperature is of the order from 400 ° C to 500 ° C, and the second predetermined temperature is in the range of 7500C to 8500C, the first predetermined temperature is in the range of 430 ° C to 460 ° C, and the second predetermined temperature is 8000C to 8500C, * said layer embodiment is made by creating a stress and relaxation layer of this layer, * said fragilized zone creation is performed by implantation, * said implantation is performed between the embodiment step and that of bonding, the implantation is carried out so as to define the zone of weakness in the thickness of the support substrate, the implantation is carried out so as to define the zone of weakness in a region of the layer created corresponding to a mesh parameter adaptation layer 10, * the substrate of the multilayer structure is silicon, the support substrate is silicon, * the layer created is SiGe or Ge, * when realized When the layer is formed, a level corresponding to a stop layer for a chemical etching during the surface treatment step is produced. During the production of the layer, three levels are formed corresponding to:> Level 1: mesh parameter adaptation layer, 20> Level 2: stop layer> Level 3: active layer of the structure to be obtained, * the materials of said layers are selected from the following: Material level 1 Material level 2 Material level 3 Ge SiGe (50/50) SiGe or Ge SiGe If SiGe or Ge * are constrained, the materials of these layers are chosen from the following: Material Level 1 Material Level 2 Material Level 3 Ge SiGe (50/50) Ge SiGe If forced SiGe * the stop layer is preserved in the final structure, * when the layer is made, two levels corresponding respectively to:> Level 1: mesh parameter adaptation layer,> Level 2: active layer of the structure e which will be obtained, the materials of said layers are selected from the following: Material Level 1 Material Level 2 Ge SiGe (50150) SiGe Si Constrained Other aspects, objects and advantages of the invention will become more apparent upon reading the present invention. following description of the invention, with reference to the accompanying drawings in which Figures la to illustrate the main steps of implementation of an embodiment of the invention.

  Referring firstly to Figure la, there is shown a support substrate 100, on which a layer 105 (shown in hatched lines) has been deposited.

  The support substrate 100 is made of a semiconductor material having a first mesh parameter. It may for example be silicon.

  Layer 105 is a layer of a material having a second mesh parameter different from the first mesh parameter mentioned above.

  The layer 105 can thus be made of SiGe, or even Ge.

  It is specified that the layer 105 is deposited by a technique making it possible to: deposit a desired thickness of a material whose mesh parameter is substantially different from the mesh parameter of the support substrate on which the deposit is made, while constituting a superficial layer of such a deposit which is substantially free from defects of the dislocation type.

  WO 00/15885 teaches for example a method for producing in this way a deposit of SiGe or Ge on silicon.

  Such a deposition method may thus be carried out, for example, according to a first mode in which a monocrystalline Ge deposition is carried out on a monocrystalline silicon support substrate, by implementing the following steps: * stabilization in temperature of the monocrystalline silicon substrate at a first predetermined stabilized temperature of 400 ° C to 5000 ° C, preferably 4300 ° C to 46 ° C, * Ge chemical vapor deposition (CVD) of Ge at said first determined temperature until a basecoat of Ge is obtained at the carrier substrate of a predetermined thickness smaller than a desired final thickness, * increasing the chemical vapor deposition temperature of Ge 20 from the first predetermined temperature to a second predetermined temperature ranging from 750 ° C to 8500 ° C, preferably 8000C to 8500C, and * further chemical vapor deposition of Ge at said second temperature p redetermined until the desired final thickness for the monocrystalline Ge layer is obtained.

  Such a deposition process may also be performed according to variants, for example those disclosed by WO 00/15885.

  Other methods for obtaining a thin layer of relaxed SiGe or of relaxed Ge, directly on a support substrate that may be made of silicon, are conceivable. For example, reference can also be made to the publication "Strain 5 relaxation of pseudomorphic Si1-xGex / Si (100) heterostructures after hydrogen or helium ion implantation for virtual substrate manufacture", B. Hollander et al., Nuclear Instrument and Metods in Physics Research B175-177 (2001) 357-367.

  In such a method, the layer 110 is made by creating a stress layer, and relaxation of this layer.

  In all cases, a layer has been made on the support substrate 100 which comprises the superficial thin layer of the structure of the structure that it is desired to manufacture.

  In this way, an intermediate wafer 10 is formed comprising on the support substrate 100 a SiGe layer 110 (with any desired Si / Ge ratio) or Ge.

  An interface 105 is thus defined between the layer 110 and the support 100. It is specified that by implementing this type of deposition process, the dislocation-type defects have been confined in the region of the layer 110 which is adjacent to the interface 105.

  By "confinement" is meant that the vast majority of dislocation type defects are in said region. The remainder of layer 110 is not absolutely free of defects, but their concentration is compatible with microelectronic applications.

  Thus, this region of the layer 110 in which the dislocation-type defects are confined constitutes a mesh parameter adaptation layer, between the silicon support substrate 100 and the surface region of the layer 110, which constitutes in itself a layer of the wafer 10 which is Ge or SiGe relaxed.

  And this layer of Ge or SiGe relaxed has a desired thickness following the deposit made at the beginning of the process. This desired thickness may in particular be of the order of 0.5 to 1 micron.

  Referring now to FIG. 11b, a weakening zone 120 is formed in the thickness of the wafer 10.

  This zone of weakness can in particular be achieved by implantation (for example of H + ions) through the layer 110.

  In this case, the implantation parameters can be defined so that the weakening zone is located in the support substrate 100, as shown in FIG. 11b.

  It is also possible to define these parameters so that the weakening zone is located in the layer 110 itself (preferably in the region of this layer which is adjacent to the interface 105).

  It is pointed out that the zone of weakness may also have been achieved by creating a porous region in the support substrate 100 before depositing the layer 110.

  The wafer comprising its embrittlement zone is then turned over and this wafer is glued with a target substrate 20.

  The target substrate 20 may be silicon.

  The face of the wafer 10 which is bonded to the target substrate is that which corresponds to the "relaxed" surface of the layer 110.

  To effect this bonding, the surfaces to be contacted have been cleaned and an adhesion layer has optionally been inserted between these surfaces. It may also be inserted between the wafer and the target substrate a layer of electrical insulation, for example an oxide.

  Such an oxide may result from the oxidation of the surface of the target substrate 20. It may also result from the oxidation of the surface of the layer 10, if it is made of SiGe.

  If the layer 110 is Ge, it is also possible to associate before bonding an oxide layer, by oxide deposition.

  The wafer and / or the target substrate can thus be associated with an insulating layer before bonding.

  After this bonding, it is possible to carry out conventional heat treatments for bonding interface consolidation.

  It is then proceeded to a detachment at the embrittlement interface, by a supply of thermal energy and / or mechanical.

  This results in a structure 30 comprising, as illustrated in FIG. 10 Id: the target substrate 20, the layer 110, optionally a residue of the support substrate 100.

  In this structure, the layer 110 itself comprises: a mesh parameter adaptation layer (part of the layer 110 which is adjacent to the residue of the support substrate 100), and a relaxed layer of desired thickness.

  In the case where the zone of weakness has been formed by implantation in the thickness of the layer 110, the resulting structure 30 does not comprise a residue of the support substrate, and a part of the parameter adaptation layer of the separated from this structure 30 during the detachment.

  In this case, the surface of the resulting structure is then treated (FIG. 1 e) to improve the surface state of the layer 110.

  This surface treatment may include polishing, and other treatments.

  In the case now that the weakening zone has been formed in the thickness of the support substrate 100 (by implantation or by a priori creation of a porous region), the residue of this support substrate is selectively etched.

  This selective attack may be a selective chemical etching, which only attacks the substrate substrate material.

  Such etching can be carried out wet (choice of a suitable etching solution), or by dry method (selected energy plasma etching, or sputtering).

  Such an etching may be preceded by polishing.

  At the end of this selective attack, the free surface of the layer 110 is treated to suppress the mesh parameter adaptation layer, which corresponds, as said, to the part of this layer 110 in which are confined the defects of the dislocation type.

  Two main variants of implementation of the invention have been described above (creation of an embrittlement zone in the support substrate, and in the layer 110 respectively).

  In both cases, the active layer of the final structure corresponds to the relaxed portion of the layer 110.

  According to a third main variant, the layer 110 is actually made up of different levels (or strata), and this layer 110 is constituted as follows: * deposition of a first level, for example by a technique such as that 20 disclosed by WO 00/15885 or by reference B. Hollander and aI mentioned above, or generally by any other known technique for producing a relaxed thin layer, * deposition of a second level, constituting a stop layer for a chemical attack, * deposition of a third level corresponding to a relaxed layer which will constitute the active layer of the final structure. This deposit is made with a desired thickness for the active layer.

  The first level corresponds to the mesh parameter adaptation layer. It can be in SiGe, even in Ge. he

  The second level must both: * have good selectivity from the third level, with respect to a chemical attack (in this respect, different materials must be used for levels 2 and 3), and * do not induce too much difference in terms of mesh parameter with the two levels surrounding it (in this respect, the materials of levels 1, 2 and 3 must not be too different).

  For example, the following combinations can be made: Material level 1 Material level 2 Material level 3 Ge SiGe (50/50) SiGe or Ge SiGe If constrained SiGe or Ge It is specified that it is preferable that layers of level 1 and 3 are Made in materials of the same nature, so that the level layer 2, interposed between these two layers, receives homogeneous stresses on both sides.

  In this case, the following materials will preferably be used: Material level 1 Material level 2 Material level 3 Ge SiGe (50/50) Ge SiGe If constrained SiGe In this third variant, the same steps of creation of embrittlement zone are carried out, The embrittlement zone can thus again be located in the layer 110. In this case, it is preferably in the thickness of the first level (in which it was then made by implantation).

  To obtain the final structure, two selective attacks are carried out: a first selective attack to eliminate the residue of the first level.

  This attack can in particular be a chemical attack, which justifies the insertion of a level corresponding to a stop layer, a second selective attack, to eliminate the stop layer itself.

  It is specified that it is also possible to form layer 110 only with two levels, including a first level as described above and a second level "gathering" levels 2 and 3 mentioned above.

  In this case, the second level may for example be of constrained silicon, while the first level is SiGe or Ge.

  And the second level then itself constitutes the active layer of the final structure, while the first level still constitutes a mesh parameter adaptation layer.

  Still in this case, the following materials can be implemented (this table, like the previous ones, is given by way of non-limiting example) Material level 1 Material level 2 Ge SiGe (50/50) SiGe If forced In all In this case, it will be possible to carry out conventional surface treatment operations after having obtained the structure of FIG.

  The invention thus makes it possible to form multilayer structures 25 comprising, for example, a layer of Ge or SiGe on a silicon substrate. It will be noted that the structures obtained by the invention are free of defects of the dislocation type, even in a buried region.

  And the structures obtained in this way can then be used to epitaxially grow on the SiGe or Ge layer additional layers, for example in constrained silicon.

  In the case where the layer of level 2 is constrained Si, it may be advantageous to realize only one selective attack in order to maintain a final structure consisting of a SiGe constrained silicon bi-layer on a silicon substrate.

  In this case, the final structure retains the barrier layer.

  Finally, it is also possible to deposit a layer of constrained silicon on the level 3 layer before the bonding step of this structure on the target substrate, in order to finally produce a structure comprising a layer of silicon constrained to a substrate of silicon.

Claims (24)

  A method of manufacturing a multilayer structure of semiconductor materials, said structure comprising a substrate (20) of a first semiconductor material and a surface thin layer of a second semiconductor material, the two semiconductor materials having substantially different mesh parameters, characterized in that the method comprises the steps of: providing a layer (110) comprising said surface thin layer on a support substrate (100), * creating an embrittlement zone in the assembly (10) formed by said support substrate and said deposited layer, 15. bonding said assembly with a target substrate (20), * detachment at this weakening zone, * surface treatment of the structure thus obtained.   2. Method according to the preceding claim, characterized in that said layer making is made by epitaxy.   3. Method according to the preceding claim, characterized in that said epitaxy is carried out with the following steps: stabilization in temperature of the support substrate at a first predetermined stabilized temperature, chemical vapor deposition at said first predetermined temperature obtaining a base layer on the support substrate of a predetermined thickness smaller than a desired final thickness for said layer (110) comprising the superficial thin layer, increasing the chemical vapor deposition temperature from the first temperature predetermined to a second predetermined temperature, and * continuing the chemical vapor deposition at said second predetermined temperature until the desired final thickness for the layer is obtained.   4. Method according to the preceding claim, characterized in that the first predetermined temperature is of the order of 4000C to 5000C, and the second predetermined temperature is of the order of 7500C to 8500C.   5. Method according to the preceding claim, characterized in that the first predetermined temperature is of the order of 430'C to 4600C, and the second predetermined temperature is of the order of 8000C to 8500C.   6. Method according to claim 1, characterized in that said layer realization is made by creating a stress and relaxation layer of this layer.   7. Method according to one of the preceding claims, characterized in that said weakened zone creation is performed by implantation.   8. Method according to the preceding claim, characterized in that said implantation is performed between the step of producing and that of bonding.   9. Method according to the preceding claim, characterized in that the implantation is performed so as to define the weakening zone in the thickness of the support substrate.   10. The method of claim 8, characterized in that the implantation is performed so as to define the weakening zone in a region of the layer (110) created corresponding to a mesh parameter adaptation layer.   11. Method according to one of the preceding claims, characterized in that prior to bonding is inserted between said assembly (10) formed by the support substrate and the deposited layer, and the target substrate (20), a layer of insulation electric.   12. Method according to the preceding claim, characterized in that prior to bonding has formed on the surface of said assembly (10) formed by the support substrate and the deposited layer an electrically insulating layer.   13. Method according to one of the two preceding claims, characterized in that prior to bonding was formed on the target substrate an electrically insulating layer.   14. Method according to one of the three preceding claims, characterized in that said electrically insulating layer is an oxide layer.   15. Method according to one of the preceding claims, characterized in that the substrate (20) of the multilayer structure is silicon.   16. Method according to one of the preceding claims, characterized in that the support substrate (100) is silicon.   17. Method according to one of the preceding claims, characterized in that the layer (110) created is SiGe or Ge.   18. Method according to one of the preceding claims, characterized in that during the production of the layer constitutes a level corresponding to a stop layer for etching during the surface treatment step.   19. Method according to the preceding claim, characterized in that during the production of the layer there are three levels corresponding respectively to: 15. Level 1: mesh parameter adaptation layer, * Level 2: stop layer , ò Level 3: active layer of the structure that will be obtained.   20. Process according to the preceding claim, characterized in that the materials of the layers corresponding to said three levels constitute one of the following combinations: Material level 1 Material level 2 Material level 3 Ge SiGe (50/50) SiGe or Ge SiGe Si constrained SiGe or Ge 21. Method according to the preceding claim, characterized in that the materials of the layers corresponding to said three levels constitute one of the following combinations: ls Material level 1 Material level 2 Material level 3 Ge SiGe (50/50) Ge SiGe If constrained SiGe 22. Method according to one of the four preceding claims, characterized in that the barrier layer is retained in the final structure.   23. A method according to claim 18, characterized in that during the production of the layer there are two levels respectively corresponding to: a Level 1: mesh parameter adaptation layer, 10 * Level 2 active layer of the structure which will be obtained.   24. Method according to the preceding claim, characterized in that the materials of the layers corresponding to said three levels constitute one of the following combinations: Material level 1 Material level 2 Ge SiGe (50/50) SiGe If forced