System for manufacturing a high-quality semiconductor single crystal, and method of manufacturing same
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.
1 . Sublimation system for growing at least one single crystal of a semiconductor material by means of a sublimation growing process, the sublimation system ( 100 ) comprising:
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; and
a thermal insulation element between the crucible ( 102 ) and the heating system;
wherein the rotary drive is coupled to the thermal insulation element and to the crucible ( 102 ), so that the thermal insulation element and the crucible ( 102 ) are rotatable with respect to the heating system.
2 . Sublimation system according to claim 1 , wherein the heating system comprises an induction coil ( 116 ) operable to generate an electro-magnetic field and/or a resistive heating coil ( 116 ), at least partly surrounding the crucible ( 102 ).
3 . Sublimation system according to claim 2 , wherein the heating system comprises an electro-magnetic field control element for steering the electro-magnetic field.
4 . Sublimation system according to claim 3 , wherein the electro-magnetic field control element comprises a metallic strut member and/or a pole piece.
5 . Sublimation system according to claim 2 , wherein the coil ( 116 ) has a deformed cross-section in at least one of its windings, and/or wherein the coil ( 116 ) has at least one winding, which is arranged to have a different distance from its neighboring windings.
6 . Sublimation system according to claim 2 , wherein the coil ( 116 ) comprises at least one electrical contact ( 124 ), which is arranged at an axial position adjacent to the crucible ( 102 ).
7 . Sublimation system according to claim 1 , wherein the rotary drive is coupled to the fixing means so that the at least one seed crystal ( 110 ) is rotatable with respect to the crucible ( 102 ).
8 . Sublimation system according to claim 1 , wherein the rotary drive is operable to cause a rotational speed in a range between 1 rpm and 60 rpm, or a rotational speed of 10 rpm.
9 . Method of growing at least one single crystal of a semiconductor material by means of a sublimation growing process, the method comprising:
providing a crucible ( 102 ) having a longitudinal axis, fixing at least one seed crystal ( 110 ) at a fixing means of the crucible, and filling a source material ( 108 ) into at least one source material compartment ( 104 );
generating, by means of a heating system, an irregular temperature field around a circumference of the crucible ( 102 ) and along the longitudinal axis of the crucible ( 102 ); and
causing a rotational movement of the fixing means around the longitudinal axis relative to the heating system, so that the growing single crystal is exposed to a time variant temperature field;
wherein a thermal insulator unit is provided between the crucible ( 102 ) and the heating system, and
wherein the crucible ( 102 ) and the thermal insulator unit are rotated in relation to the heating system.
10 . Method according to claim 9 , wherein the fixing means is rotated in relation to the thermal insulator unit.
11 . Method according to claim 9 , wherein the crucible is rotated in relation to the heating system and/or in relation to the thermal insulator unit provided between the crucible and the heating system.
12 . Method according to claim 9 , wherein the rotational movement is performed with a rotational speed in a range between 1 rpm and 60 rpm, or with a rotational speed of 10 rpm.
13 . Method according to claim 9 , wherein the generated irregular temperature field has regions which differ from each other by at least 2 K and not more than 15 K, or which differ by 5 K from each other.