TWO-STEP ION IMPLANTATION METHOD WITH ACTIVE WAFER COOLING FOR BURIED OXIDE FORMATION

摘要

The present invention provides methods and system for forming a buried oxide layer (BOX) region in a semiconductor substrate, such as, a silicon wafer. In one aspect, in a method of the invention, an initial dose of oxygen ions is implanted in the substrate while maintaining the substrate temperature in a range of about 300 °C to 600 °C. Subsequently, a second dose of oxygen ions is implanted in the substrate while actively cooling the substrate to maintain the substrate temperature in range 50 °C to 150 °C. These ion implantation steps are followed by an annealing step in an oxygen containing atmosphere to form a continuous BOX region in the substrate. In one preferred embodiment, the initial ion implantation step is performed in a chamber that includes a device for heating the substrate while the second ion implantation step is performed in a separate chamber that is equipped with a device for actively cooling the substrate. The annealing step can be performed in a third chamber or in either of the first or second chambers.