Independent control of temperature coefficient and breakdown voltage in Zener diodes

The temperature coefficient of the breakdown voltage of a Zener (voltage-reference) diode has become accepted as an implicit function of the breakdown voltage. The letter describes a simple technique whereby the temperature coefficient may be independently controlled by altering the doping profile. To illustrate the technique, design criteria for a silicon diode with a breakdown voltage of 20 V and a nominally zero temperature coefficient are derived.