High performance bipolar transistors fabricated by post emitter

Details High performance bipolar transistors fabricated by post emitter High performance bipolar transistors fabricated by post emitter

1979-09-21

1981-01-06

Tupman, W. C.

Metal working

Method of mechanical manufacture

Assembling or joining

29580, 29591, 204 15, 357 91, B01J 1700

Patent

active

042427916

ABSTRACT:
Disclosed is a method for fabricating very high performance semiconductor devices, particularly bipolar-type transistors having a heavily doped inactive base and a lightly doped narrow active base formed by ion implantation. In order to prevent the high dose boron implantation, for an NPN transistor, from getting into the active base region, a self-aligned mask covering the emitter contact i.e., active base region, is required for inactive base implantation. The self-aligned mask is anodically oxidized aluminum pads. The device wafer metallized with blanket aluminum film is immersed in a dilute H.sub.2 SO.sub.4 solution electrolytic cell which selectively anodizes only the aluminum lands situated over the Si.sub.3 N.sub.4 /SiO.sub.2 defined device contact windows. The aluminum oxide formed by anodization process is porous but may be sealed and densified. The aluminum film that is not anodized is then selectively etched off using either chemical solution or sputter etching. Using the aluminum oxide formed over the contact windows to mask the active base region, a high dose boron implantation is made through the Si.sub.3 N.sub.4 /SiO.sub.2 layers to dope the external base region. After stripping the aluminum oxide from the emitter contact window, the emitter with a desired concentration profile and junction depth is subsequently formed. Formation of the active base is formed by a low dose boron implantation made with its concentration peak below the emitter. A relatively low temperature annealing, as for example, 900.degree. C., is used to fully activate the implanted boron and minimize the redistribution of the active base doping profile. The device thus formed will have a controllable narrow base width and doping profile.

REFERENCES:
patent: 3595716 (1971-07-01), Kerr

Affiliated with

Also associated with

Rating

High performance bipolar transistors fabricated by post emitter does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with High performance bipolar transistors fabricated by post emitter , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High performance bipolar transistors fabricated by post emitter will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-278785