An electrostatic chuck 20 for holding a substrate 12 in a process chamber, comprises a unitary monolithic structure 25 of monocrystalline ceramic. The monocrystalline monolith has an electrode 45 embedded therein for electrostatically holding the substrate 12 upon application of a voltage thereto. An electrical connector 50 extends through the unitary monolithic structure 25 for supplying a voltage to the electrode 45. In one version, the monolithic structure 25 is made from a single piece of monocrystalline ceramic formed by a melt forming process. In another version, the monolithic structure 25 comprises a plurality of monocrystalline ceramic plates 270 bonded to one another to form the monolithic structure 25. Preferably, the monolithic structure 25 comprises monocrystalline sapphire and the electrode 45 comprises a refractory metal.