Method of Growing Lattice Constant Matched, Low Resistivity Silicon Crystals for CMOS Epitaxial Substrate
Original Publication Date: 1988-Jun-01
Included in the Prior Art Database: 2005-Feb-15
An axial magnetic field is applied in Czochralski (CZ) crystal growth to provide constant impurity concentration, thereby keeping the lattice constant across the whole length of the crystal in heavily doped p+ silicon crystals. High performance complementary metal-oxide semiconductors (CMOS) require heavily doped low resistivity Si crystals lattice constant matched to the lightly doped epitaxial layer. One method to accomplish this is to dope the Si crystal, during growth, with an electronically inactive inert dopant, such as germanium to achieve the lattice constant matching. In the conventional CZ silicon crystal growth where a quasi-complete solute transport prevails, it is not possible to maintain the ratio constant across the length of the crystal.