I became discouraged of finding a suitable low-capacitance zener to protect the MOSFET gates in my high-voltage amplifier designs. (The protection may be optional, but one sleeps better with it in place.) Even the 50uA-rated low-current zener diodes are in fact larger-die types, with high capacitance. For example, the 7.5-volt MMSZ4693 has about 130pF at zero volts.
My solution was to use a Diodes, Inc. D1213A-01WS TVS device, which has a 6 to
10V breakdown and an amazing low 1pF of capacitance. But this can carry limited current in the forward direction, so I added a BAT54WS Schottky diode in parallel. Both devices are in small SOD-323 packages. Total capacitance, 11pF at their zero volt maximum, which doesn't add too awfully much to the 38pF Ciss of the small high-voltage power MOSFETs I'm using.Or maybe one of you has discovered a better solution?