High energy aluminum ion implantation using a variable energy RFQ ion implanter

A high energy aluminum ion implantation technique has been studied for the fabrication of high power semiconductor devices. A high current MeV ion implanter using a variable energy RFQ linac was developed and tested for pulse mode long time operation. This system consists of a microwave multiply charged ion source, a sector type mass separator, a magnetic quadrupole triplet, a variable energy RFQ linac, a bending magnet, and an implantation chamber. The RFQ linac is driven by an r.f. resonance circuit with an external variable inductance coil. It is tuned so that the acceleration energy of aluminum ions is 0.9 MeV. Repetition and pulse width of the beam are 1 Hz and 500 ms, respectively. The ions am implanted into 6-inch silicon wafers, and the depth profile and dose uniformity are measured. Results show that the depth and dose uniformity are 1.35 μm and 0.7%, respectively. This system is useful not only for fabrication of power semiconductor devices but also for ULSI semiconductor devices with high throughput