Characteristics of high performance microwave transistors fabricated by ion implantation

In this paper the characteristics and fabrication of implanted microwave transistors are discussed. By use of arsenic implanted emitter and boron implanted base, devices can be fabricated with f T between 4.0 and 7.0 GHz, while f max ranges from 18.0 to 25.5 GHz. Noise figures range from 3.8 to 5.5 db at 4 GHz. Results will be presented from devices implanted with arsenio emitter energies from 27 to 30 KeV and boron base energies from 20 to 38 KeV. Boron base doses range from 5 \times 10^{12} to 1013B/cm2, while emitter dose was 1 \times 10^{15} to 2 \times 10^{15} As/cm2. It was found that (Q E /D E ) eff ranged from 1.5 to 2.5 \times 10^{13} cm-4sec for all emitter implants. A discussion of improvement of uniformity and yield is included along with some wafer yield data.