New technique for fabrication of low voltage Si Zener diodes

A new technique for fabrication of low voltage Si Zener diodes is suggested, which consists of two successive diffusions (first a deep phosphorus diffusion and then a shallow boron diffusion) into an n-type Si epitaxial layer. Also, a new analytical expression for differential resistance of low voltage Si Zener diodes in the breakdown region is derived, which describes remarkably well the experimental results.