US 5969403 A A fuse for an integrated circuit is constituted by
a shallow NP junction, covered with a metal contact, the
semiconductor region being not excessively doped. For the
blowing of the fuse, the junction is forward biased with a
current sufficient to enable a diffusion of metal up to the
junction. This short-circuits the junction. The detection is
done also by the forward biasing of the junction, but with a low
current or a low voltage. The detection can also be done with
reverse biasing. 1. A physical fuse circuit with a low blow-out
voltage and a low blow-out current density for integrated
circuits formed in a semiconductor substrate, including a
circuit for blowing the fuse, comprising: a shallow, doped first
semiconductor region having a first conductivity type, diffused
in a second semiconductor region having a second conductivity
type that is opposite to the first conductivity type; and a
diffusion metal layer formed in direct contact with the doped
first semiconductor region; wherein the first