Manufacturable AlGaAs/GaAs HBT Implant Isolation Process Using Doubly Charged Helium
A U T H O R / C R E D I T S
Rainier Lee, Shiban Tiku, and Wanming Sun
Conexant Systems, 2427 W. Hillcrest Drive
Newbury Park, CA 91320 (805) 480-4339
A B S T R A C T
Beam of doubly charged helium (He++) with an energy from 380 to 420 KeV has been used to implant isolate AlGaAs/GaAs heterojunction bipolar transistor (HBT) devices. Commercially available 250KV medium current implanters were used with minor equipment modifications. Isolation resistance values decreased from 140 to 20 MW as the implant dose was increased from 0.7 to 1.5E14 atoms/cm2. Gain of HBT amplifiers were affected by the implant parameters. Initial reliability study of singly ionized helium (He+) and He++ implanted devices showed no significant differences.