Before revision: This implies that the MESFET gate should, in transistor mode, be biased such that one does not have a forward-conducting metal–semiconductor diode instead of a reversed-biased depletion zone controlling the underlying channel.
After revision: This implies that the MESFET gate should, in transistor mode, be biased such that one has achannel, rather than a forward-conducting metal–semiconductor diode to the reversed-biased depletion zone controlling the underlying channel.