Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D8/00—Diodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
  • H10D62/50—Physical imperfections
  • H10D62/53—Physical imperfections the imperfections being within the semiconductor body 
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
  • H10D62/60—Impurity distributions or concentrations

Definitions

• the invention relates to a method for producing a body from doped semiconductor material with a certain mean free path for free charge carriers and a mean free path length for the free charge carriers, which is smaller than the certain mean free path.
• This body has a transition between doped semiconductor material of one conductivity type and doped semiconductor material of a conductivity type opposite to one conductivity type.
• the body's ability to block is increased due to the smaller mean free path.
• the object of the invention is to provide a simple method for producing a body of the type mentioned, which has a region of reduced mean free path that only extends locally and does not extend over the whole body.
• the method specified in claim 1, which according to the invention comprises the step: Growing by epitaxy on a substrate crystal made of doped semiconductor material with the determined mean free path length for the free charge carriers of a crystal layer made of doped semiconductor material which at least locally has a mean mean free path length for the free charge carriers that is smaller than the determined mean free path length.
• the method according to claim 1 preferably and advantageously has the steps:
• the scattering centers reduce the determined mean free path for the free charge carriers of the crystal layer, so that the crystal layer with the scattering centers has a smaller mean free path for the free charge carriers.
• the scattering centers can be distributed over the entire surface of the crystal layer, so that the mean free path length of the crystal layer over the entire surface of the crystal layer is reduced, or they can advantageously only be present locally at one or more specific locations on the surface of the crystal layer, so that the mean free path length is reduced only over part of the surface of the crystal layer.
• the reduced mean free path is essentially limited to the extent of the crystal layer and does not extend to areas of the body outside the crystal layer.
• the scattering centers in the crystal layer are preferably and advantageously produced by introducing non-doping foreign substance particles into the crystal layer.
• Foreign matter particles are preferably foreign matter atoms
• Non-doping * means that the foreign matter particles have no influence on the conductivity of the doped semiconductor material into which they are introduced. The foreign matter particles only act as scattering centers in the semiconductor material, which reduce the mean free path already existing in the semiconductor material.
• Scattering centers can advantageously be created by adding non-doping foreign matter particles during the growth of the crystal layer in the crystal layer.
• scattering centers can also be generated by diffusing non-doping foreign matter particles into the crystal layer.
• further doped semiconductor material of the body is applied to the crystal layer with the smaller mean free path for the free charge carriers, which has a mean free path length for the free charge carriers that is equal to or greater than the determined mean free path length for the free charge carriers is.
• the further doped semiconductor material of the body can advantageously have at least one crystal layer of doped semiconductor material that has been grown by epitaxy on the crystal layer with the smaller mean free path, it can also have a crystal body of doped semiconductor material that is bonded to an exposed crystal layer on the substrate crystal by wafer bonding , The crystal body can accordingly be connected to the crystal layer with the smaller mean free path or to a crystal layer grown on this crystal layer.
• the further doped semiconductor material of the body preferably and advantageously has a conductivity type that is opposite to a conductivity type of the substrate crystal, and the crystal layer with the smaller mean free path length has the conductivity type of the substrate crystal and / or the opposite conductivity type of the further doped semiconductor material of the body.
• the method according to claim 2 preferably and advantageously has the step of producing the crystal body with the smaller mean free path length by using a crystal body made of doped semiconductor material with the determined mean free path length for the free charge carriers and - Generation of scattering centers in this crystal body of the determined mean free path.
• the crystal body here is not to be understood as an epitaxial crystal layer alone, but rather a compact crystal body, for example grown by crystal growing, e.g. all or part of a single-crystalline wafer made of semiconductor material.
• the crystal body can, for example, also have a substrate crystal made of semiconductor material, on which one or more epitaxial layers are made
• Semiconductor material have grown, which together with the substrate crystal form the crystal body.
• the scattering centers reduce the determined mean free path for the free charge carriers of the crystal body, so that the crystal body with the scattering centers has a smaller mean free path for the free charge carriers.
• the scattering centers can be distributed over an entire cross-sectional area of the crystal body so that the mean free path length of the crystal layer is reduced over this entire cross-sectional area of the crystal body, or they can advantageously only be present locally at one or more specific locations on the cross-sectional area of the crystal body. so that the mean free path length is only reduced over part of the cross-sectional area of the crystal body.
• the reduced mean free path is essentially restricted to the extent of this crystal body and does not extend to regions of the body made of doped semiconductor material outside of this crystal body.
• scattering centers are generated in the crystal body of the determined mean free path by introducing non-doping foreign matter particles into the crystal body.
• Scattering centers can advantageously be generated by adding non-doping foreign matter particles during the growth of the crystal body of the determined mean free path length in the crystal body.
• Scattering centers can alternatively or additionally also by
• inventive method according to claims 1 and 2 also creates novel bodies made of doped semiconductor material, which are specified in claims 17 and 19.
• FIG. 1 shows a side view of a substrate crystal made of doped semiconductor material as the output stage of an exemplary method according to the invention
• FIG. 2 shows the substrate crystal according to FIG. 1 during the growth of an epitaxial crystal layer made of doped semiconductor material on the substrate crystal with the addition of non-doping foreign matter particles that create scattering centers in the crystal layer,
• FIG. 3 shows the body made of doped semiconductor material according to FIG. 2 after completion of the growth of the epitaxial crystal layer made of doped semiconductor material on the substrate crystal with the addition of non-doping foreign matter particles which generate scattering centers in the crystal layer,
• Figure 4 shows the body made of doped semiconductor material
• FIG. 3 after application of further doped semiconductor material to the epitaxial crystal layer,
• FIG. 5 shows a side view of a body according to the invention, consisting of a single-crystalline crystal body made of doped semiconductor material, which has a region in which an average free path length for free charge carriers is reduced, and of a further single-crystalline crystal body made of doped semiconductor material, which is connected to the one crystal body , the connection being made by wafer bonding, and
• FIG. 6 shows a side view of one crystal body during the production of the area of reduced mean free path length by creating scattering centers in the crystal body.
• a crystal layer of doped semiconductor material is grown on a surface of a substrate crystal 10 made of doped semiconductor material, for example on the upward-facing surface 11 of crystal 10, by epitaxy.
• the doped semiconductor material of the substrate crystal 10 is, for example, n-doped and has a certain mean free path for free charge carriers CP, for the most part electrons in the example. If the semiconductor material of the substrate crystal 10 is p-doped, the free charge carriers CP are mostly holes.
• the determined mean free path length for the free charge carriers CP of the substrate crystal 10 is, for example, the mean free path length ⁇ n naturally present in the doped semiconductor material of the substrate crystal 10 for the free charge carriers CP.
• the doped semiconductor material of the crystal layer to be grown is selected, for example, from the same conductivity type as the doped semiconductor material of the substrate crystal 10, that is to say n-doped in the example.
• the doped semiconductor material of the crystal layer to be grown has a certain mean free path length for the free charge carriers CP, which is the average free path length for the free charge carriers CP naturally present in the doped semiconductor material of the crystal layer to be grown, for the most part in the example Electrons.
• the semiconductor material of the crystal layer to be grown is so different from the semiconductor material of the substrate crystal 10 that the determined mean free path length for the free charge carriers CP of the crystal layer to be grown is smaller than the determined mean free path length for the same free charge carriers CP of the substrate crystal 10 , a body according to the invention has already been realized.
• the same doped semiconductor material as for the substrate crystal 10 which has the same determined mean free path length ⁇ n for at least this part of the crystal layer to be grown and the substrate crystal 10 for the same free charge carriers CP, and the comparatively smaller mean free path length for the same free charge carrier CP is produced by generating scattering centers in the crystal layer, which reduce the determined mean free path length for the free charge carriers CP of the crystal layer.
• the scattering centers in the crystal layer are preferably generated by introducing non-doping foreign matter particles into the crystal layer, advantageously by adding non-doping foreign matter particles during the growth of the crystal layer to this layer.
• FIG. 2 shows the substrate crystal 10 during the epitaxial growth of the crystal layer on the surface 11 of the substrate crystal 10, wherein a part of the crystal layer designated 20 at the substrate crystal 10 has already grown on this surface 11.
• liquid phase, gas phase and / or molecular beam epitaxy can be used to grow the crystal layer 20.
• the phase and / or the molecular beam are added, for example, to the non-doping foreign substance particles, for example non-doping foreign substance atoms, which are indicated by points 21 in FIG. 2 and define scattering centers 21 in the crystal layer 20 grown on the surface 11 of the substrate crystal.
• the exemplary body 1 according to the invention shown in FIG. tall slaughter 20 arose in which the determined mean free path length ⁇ n for the free charge carriers CP is reduced to the smaller mean free path length ⁇ r for these charge carriers CP by the introduced scattering centers 21 ⁇ .
• the non-doping scattering centers 21 may be distributed in the x layer 20 20 over the entire surface of the crystal layer, for example, uniform. This area is represented, for example, by the area 201 of the crystal layer 20 facing away from the substrate crystal 10. In this case, the mean free path for the free charge carriers is reduced over the entire area 201.
• the scattering centers 21 ⁇ can also be distributed only over one or more partial areas of the surface 201 in the crystal layer 20 and are absent outside these partial areas. In this case, the average free path length for the free charge carriers is only reduced over the partial area or areas and outside of these partial areas there is the determined average free path length ⁇ n for the free charge carriers CP in layer 20.
• the mean free path length for the free charge carriers in the crystal layer 20 can be varied in the direction x perpendicular to the surface 201 of the layer 20, ie in the direction perpendicular to the surface 11 of the substrate crystal 10.
• the substrate crystal 10 and the crystal layer 20 each consist of silicon, and the scattering centers 21 are defined by foreign substance particles 21 in the form of germanium atoms and / or carbon atoms.
• the scattering centers 21 may ⁇ Vietnamesedotierender by diffusing impurity particles 21 after completion of the epitaxial growth in the finished crystal layer 20 are produced.
• a part 20 ⁇ bordering on the surface 11 of the substrate crystal 10 preferably consists of semiconductor material of the same conductivity type as the semiconductor material of the crystal body 10 of the crystal layer 20, in the example case of the conductivity type n, and on a surface 202 of this part facing away from surface 11 of the substrate crystal 10 20 ⁇ borders a part 20 made of semiconductor material of the conductivity type p of the crystal layer 20 opposite to the semiconductor material of the crystal body 10, which part 20 20X also borders on the surface 201 of the crystal layer 20 facing away from the substrate crystal 10.
• the crystal layer 20 and thus the body 1 has a pn junction 100 between the p-doped semiconductor material and the n-doped semiconductor material.
• This junction 100 extends in the interface between the n-doped semiconductor material and the p-doped semiconductor material of the crystal layer 20, i.e. in surface 202 of crystal layer 20.
• FIG. 4 shows a further development of the body 1 according to FIG. 3 in such a way that further doped semiconductor material 30 of the body 1 is applied to the crystal layer 20 of the body 1, which has the smaller mean free path length ⁇ r for the free charge carriers CP has an average free path length ⁇ n for the free charge carriers CP which is greater than the smaller mean free path length ⁇ r for the free charge carriers CP of the crystal layer 20.
• the further doped semiconductor material 30 of the body 1 can, for example, be epitaxially applied to the Surface 201 of the crystal layer 20 with the smaller mean free path length ⁇ r grown crystal layer consist of doped semiconductor material.
• the semiconductor material 30 can also consist of a single-crystalline crystal body made of doped semiconductor material, for example similar to the substrate crystal 10, which is bonded to an exposed crystal layer on the substrate crystal 10 by wafer bonding.
• the surface 31 of the crystal body 30 facing the crystal layer 20 and the surface 201 of the crystal layer 20 are connected to one another, the connection 23 between the two surfaces 31 and 201 being produced by wafer bonding.
• Wafer bonding in itself is a well-known joining technique
• the further doped semiconductor material 30 of the body is p-doped and thus doped in the opposite way to the substrate crystal 10.
• This embodiment of the body 1 according to FIG. 4 has particular advantages if the mean free path length of the n-doped semiconductor material of the crystal layer 20 varies in the direction x perpendicular to the surface 201 of the crystal layer 20 in such a way that the mean free path length is reduced there more , where an electric field strength is higher in the crystal layer 20 and less strongly reduced where the electric field strength is smaller in the crystal layer 20.
• Such field strengths are known to occur when an electrical reverse voltage is applied to the junction 100.
• the so-called critical electric field strength can be increased particularly advantageously, and thus, with a certain applied blocking voltage, the required thickness of a zone in the body 1 which is necessary for this blocking voltage to be reached required space charge zone can be significantly reduced.
• a body 1 can now also be used for electronic components with high blocking capacity, e.g. 2 to 6 kV the electrically active zone can be produced completely by epitaxy.
• the invention provides a novel body 1 made of doped semiconductor material, which has a substrate crystal 10 made of doped semiconductor material with a specific mean free path length ⁇ n for free charge carriers CP and an epitaxial crystal layer 20 made of doped semiconductor material on the substrate crystal 10, which at least locally has one determined mean free path length ⁇ n has a smaller mean free path length ⁇ r for the free charge carriers CP.
• a preferred and advantageous embodiment of this body 1 has at least one pn junction 100 between p-doped semiconductor material and n-doped semiconductor material.
• the crystal layer 20 can consist of p- and / or n-doped semiconductor material. In the embodiment according to FIG. 4, for example, the crystal layer 20 consists of p- and n-doped semiconductor material and the pn junction 100 extends in the surface 202 of the crystal layer 20.
• the pn junction 100 would extend in the surface 11 of the substrate crystal 10.
• the pn junction 100 would extend in the surface 11 of the substrate crystal 10.
• the body 1 shown in FIG. 5 made of doped semiconductor material has a uniform crystal body 10 'made of doped semiconductor material with a certain mean free path length ⁇ n for free charge carriers CP, which in a surface 11' of the crystal body 10 'facing for example upwards bordering region 20 'has a mean free path length ⁇ r smaller than the determined mean free path length ⁇ n for the free charge carriers CP.
• the region 20 may extend ⁇ 11 over the entire surface 11 ', or only one or more subregions of the surface. In the direction x ⁇ perpendicular to the surface 11 of the crystal body 10 ', the region 20 ⁇ extends , preferably only over part of the crystal body 10'.
• the smaller mean free path length ⁇ r can vary in this direction x ⁇ .
• Another uniform crystal body 10 ′′ made of doped semiconductor material is connected to the crystal body 10 ′, the semiconductor material of which has an average free path length ⁇ n ′ for the free charge carriers CP that is greater than the smaller mean free path length ⁇ r of the crystal body 10 'is.
• the connection between the two crystal bodies 10 'and 10' is made by wafer bonding.
• the mutually facing surfaces 11 'and 11''of the crystal bodies 10' and 10 '' are connected to one another, the connection 111 between the two surfaces 11 'and 11''being produced by wafer bonding.
• the crystal body 10 ' is n-doped and the crystal body 10''is p-doped, which means that the body 1 according to FIG. 5 has a pn junction 100' between the p-doped semiconductor material and the n-doped semiconductor material.
• This transition 100 ' extends in the interface between the n-doped crystal body 10 ⁇ and the p-doped crystal body 10 ⁇ , ie along the surfaces 11' and 11 '' of the crystal bodies 10 'and 10 ".
• the region 20 X ⁇ of the smaller mean free path length ⁇ r is defined by scattering centers 21 ⁇ in the crystal body 10 ⁇ , which are distributed in the crystal body 10 and reduce the determined mean free path length ⁇ n of the semiconductor material of this body 10 ⁇ .
• the scattering centers 21 can be generated similarly to the body 1 according to FIGS. 2 to 4 and, as indicated in FIG. 6, by introducing non-doping foreign substance particles 21 into the crystal body 10 ⁇ , for example by adding non-doping foreign substance particles 21 during the growth of the crystal body 10 mean free path length ⁇ n in the crystal body 10 ⁇ and / or by diffusing non-doping foreign matter particles 21 into the crystal body 10 ⁇ .
• An x x varying in the direction of smaller mean free path .lambda.r can be generated by the fact that during the growth of the crystal body a is used to generate scattering centers in the crystal 21 ⁇ body 10 offered amount memoridotierender impurity particles 21 varies over time.
• the crystal body 10 ⁇ and / or the crystal body 10 ⁇ can be thinned by polishing and / or etching steps. Then, if necessary, further method steps that are necessary for the completion of the component can be carried out.

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• 2000
  • 2000-09-29 DE DE10048437A patent/DE10048437A1/de not_active Ceased
• 2001
  • 2001-08-27 JP JP2002531498A patent/JP2004510354A/ja active Pending
  • 2001-08-27 EP EP01985777A patent/EP1320897B1/de not_active Expired - Lifetime
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  • 2001-08-27 WO PCT/EP2001/009866 patent/WO2002027802A1/de not_active Ceased
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