Abstract: The present invention relates to a silicon carbide substrate for use as a crystal seed, comprising a monocrystalline silicon carbide disk covered with a protective oxide layer. The protective oxide layer is intended to be removed to expose an ideal, clean surface of the monocrystalline silicon carbide disk. The present invention also relates to a method of producing at least one bulk silicon carbide single-crystal by sublimation growth using the silicon carbide substrate with protective oxide layer as a seed crystal. The protective oxide layer is removed from the seed crystal surface to expose the underlying monocrystalline silicon carbide disk by a back-etching process performed in-situ in the crystal growth crucible, i.e. after the seed crystal is arranged inside the growth crucible and before the sublimation deposition on the growth surface starts.

Abstract: Thermal post-treatment of a silicon carbide (SiC) volume monocrystal which has a substantially cylindrical basic shape with a crystal length in an axial direction, a crystal diameter in a radial direction, a crystal central longitudinal axis extending in the axial direction, and with three boundary surfaces, namely, a bottom surface, a top surface and a circumferential edge surface. The SiC volume monocrystal is brought to a post-treatment temperature in order to reduce mechanical stresses present in the SiC volume monocrystal after completion of the previous growth, wherein an inhomogeneous temperature profile with a radial thermal gradient is set in the SiC volume monocrystal, which rises continuously from the crystal central longitudinal axis to the circumferential edge surface, and a heat exchange of the SiC volume monocrystal with a surrounding free space takes place via free heat radiation on at least two of the three boundary surfaces.

Abstract: The present invention relates to systems and methods for growing bulk semiconductor single crystals, and more specifically, for growing bulk semiconductor single crystals, such as silicon carbide, based on physical vapor transport. The sublimation system comprises a crucible (102) having a longitudinal axis (120) and a sidewall (116) extending along the longitudinal axis (120), wherein the crucible comprises a fixing means for at least one seed crystal (110) and at least one source material compartment (104) for containing a source material (108), and a heating system being formed to generate a temperature field around a circumference of the crucible along the longitudinal axis of the crucible, wherein the crucible (102) comprises at least one first heat radiation cavity (118), which is arranged opposite to the fixing means and adjacent to the source material compartment (104), the first heat radiation cavity (118) being closed on all of its sides.

Abstract: The present invention relates to systems and methods for growing bulk semiconductor single crystals, and more specifically, for growing bulk semiconductor single crystals, such as silicon carbide, based on physical vapor transport. The sublimation system comprises a crucible (202) having a longitudinal axis (212) and a sidewall (218) extending along the longitudinal axis (212), wherein the crucible (202) comprises a fixing means for at least one seed crystal (210) and at least one source material compartment (204) for containing a source material (208); and a heating system for generating a temperature field around a circumference of the crucible (202) along the longitudinal axis (212) of the crucible (202); a thermally insulating unit (214) arranged within the source material compartment (204) at the sidewall (218) of the crucible (202).

Abstract: The present invention relates to systems and methods for growing bulk semiconductor single crystals, and more specifically, for growing a bulk semiconductor single crystals, such as silicon carbide, based on physical vapor transport. A sublimation system for growing at least one single crystal of a semiconductor material by means of a sublimation growing process comprises a crucible (102) having a longitudinal axis (120) and comprising a fixing means for at least one seed crystal (110) and at least one source material compartment (104) for containing a source material (108); a heating system being formed to generate an irregular temperature field around a circumference of the crucible at one or more defined heights along the longitudinal axis of the crucible; a rotary drive that is operable to cause a rotational movement of the fixing means around the longitudinal axis relative to the heating system.

Abstract: The present invention relates to systems and methods for growing bulk semiconductor single crystals, and more specifically, for growing a bulk semiconductor single crystals, such as silicon carbide, based on physical vapor transport. A sublimation system for growing at least one single crystal of a semiconductor material by means of a sublimation growing process comprises a crucible (102) having a longitudinal axis (120) and comprising a fixing means for at least one seed crystal (110) and at least one source material compartment (104) for containing a source material (108); a heating system being formed to generate an irregular temperature field around a circumference of the crucible (102) and/or along the longitudinal axis of the crucible (102); a thermal insulation unit (117) at least partly surrounding the crucible (102), wherein the thermal insulation unit (117) has a radially and/or axially asymmetric form to compensate the irregular temperature field.

Abstract: An SiC volume monocrystal is processed by sublimation growth. An SiC seed crystal is placed in a crystal growth region of a growing crucible and SiC source material is introduced into an SiC storage region. During growth, at a growth temperature of up to 2,400° C. and a growth pressure between 0.1 mbar and 100 mbar, an SiC growth gas phase is generated by sublimation of the SiC source material and by transport of the sublimated gaseous components into the crystal growth region, where an SiC volume monocrystal grows by deposition from the SiC growth gas phase on the SiC seed crystal. A mechanical stress is introduced into the SiC seed crystal at room temperature prior to the start of the growth to cause seed screw dislocations present in the SiC seed crystal to undergo a dislocation movement so that seed screw dislocations recombine.

Abstract: A SiC volume monocrystal is produced by sublimation growth. An SiC seed crystal is placed in a crystal growth region of a growing crucible and SiC source material is introduced into an SiC storage region. During growth, at a growth temperature of up to 2,400° C. and a growth pressure between 0.1 mbar and 100 mbar, an SiC growth gas phase is generated by sublimation of the SiC source material and by transport of the sublimated gaseous components into the crystal growth region, where an SiC volume monocrystal grows by deposition from the SiC growth gas phase on the SiC seed crystal. Prior to the start of growth, the SiC seed crystal is examined at the growth surface for the presence of seed screw dislocations, nucleation centers are generated, wherein the nucleation centers are starting points for at least one compensation screw dislocation during the growth carried out subsequently.

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at maximum 5·1018 cm?3, preferably 1·1018 cm?3, from the mean concentration of this dopant in the peripheral region (104).

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at least 1·1018 cm?3 from the mean concentration of this dopant in the peripheral region (104).

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at least 1-1018 cm-3 from the mean concentration of this dopant in the peripheral region (104).

Abstract: The present invention relates to a chamfered silicon carbide substrate which is essentially monocrystalline, and to a corresponding method of chamfering a silicon carbide substrate. A silicon carbide substrate according to the invention comprises a main surface (102), wherein an orientation of said main surface (102) is such that a normal vector ({right arrow over (O)}) of the main surface (102) includes a tilt angle with a normal vector ({right arrow over (N)}) of a basal lattice plane (106) of the substrate, and a chamfered peripheral region (110), wherein a surface of the chamfered peripheral region includes a bevel angle with said main surface, wherein said bevel angle is chosen so that, in more than 75% of the peripheral region, normal vectors ({right arrow over (F)}_i) of the chamfered peripheral region (110) differ from the normal vector of the basal lattice plane by less than a difference between the normal vector of the main surface and the normal vector of the basal lattice plane of the substrate.

Abstract: The present invention relates to a chamfered silicon carbide substrate which is essentially monocrystalline, and to a corresponding method of chamfering a silicon carbide substrate. A silicon carbide substrate according to the invention comprises a main surface (102), wherein an orientation of said main surface (102) is such that a normal vector ({right arrow over (O)}) of the main surface (102) includes a tilt angle with a normal vector ({right arrow over (N)}) of a basal lattice plane (106) of the substrate, and a chamfered peripheral region (110), wherein a surface of the chamfered peripheral region includes a bevel angle with said main surface, wherein said bevel angle is chosen so that, in more than 75% of the peripheral region, normal vectors ({right arrow over (F)}_i) of the chamfered peripheral region (110) differ from the normal vector of the basal lattice plane by less than a difference between the normal vector of the main surface and the normal vector of the basal lattice plane of the substrate.

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at maximum 5·1018 cm?3, preferably 1·1018 cm?3, from the mean concentration of this dopant in the peripheral region (104).

Abstract: A bulk SiC single crystal is produced by placing an SiC seed crystal in a crystal growth region of a growth crucible, and introducing SiC source material into an SiC reservoir region, and the bulk SiC single crystal is grown on from an SiC growth gas phase by deposition. The growth crucible is surrounded by an insulation that extends rotationally symmetrically and axially towards the central middle longitudinal axis. The insulation has mutually concentric insulation cylinder components and the insulation is notionally divided into insulation ring segments that are in turn notionally divided into volume elements. The insulation cylinder components are selected and positioned relative to one another such that every volume element of the insulation ring segment in question has a volume element density varying by not more than 10% from an average insulation ring segment density of the insulation ring segment in question.

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at maximum 5·1018 cm?3, preferably 1·1018 cm?3, from the mean concentration of this dopant in the peripheral region (104).

Abstract: The present invention relates to a chamfered silicon carbide substrate which is essentially monocrystalline, and to a corresponding method of chamfering a silicon carbide substrate. The silicon carbide substrate (100) comprises a main surface (102) and a circumferential end face surface (114) which is essentially perpendicular to the main surface (102), and a chamfered peripheral region (110), wherein a first bevel surface (106) of the chamfered peripheral region (110) includes a first bevel angle (a1) with said main surface (102), and wherein a second bevel surface (108) of the chamfered peripheral region (110) includes a second bevel angle (a2) with said end face surface (114), wherein, in more than 75% of the peripheral region, said first bevel angle (a1) has a value in a range between 20° and 50°, and said second bevel angle (a2) has a value in a range between 45° and 75°.

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at maximum 5·1018 cm?3, preferably 1·1018 cm?3, from the mean concentration of this dopant in the peripheral region (104).

Abstract: A bulk SiC single crystal is produced by placing an SiC seed crystal in a crystal growth region of a growth crucible, and introducing SiC source material into an SiC reservoir region, and the bulk SiC single crystal is grown on from an SiC growth gas phase by deposition. The growth crucible is surrounded by an insulation that extends rotationally symmetrically and axially towards the central middle longitudinal axis. The insulation has mutually concentric insulation cylinder components and the insulation is notionally divided into insulation ring segments that are in turn notionally divided into volume elements. The insulation cylinder components are selected and positioned relative to one another such that every volume element of the insulation ring segment in question has a volume element density varying by not more than 10% from an average insulation ring segment density of the insulation ring segment in question.

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at least 1-1018 cm-3 from the mean concentration of this dopant in the peripheral region (104).