Cascode amplifier structures including wide bandgap field effect transistor with field plates

A multi-stage amplifier block, comprising:

• a first stage transistor arranged to provide current gain;
• a second stage transistor having a field plate, said first transistor coupled to said second transistor with said second transistor providing voltage gain,
• wherein said field plate is electrically connected to the gate of said second transistor,
• wherein said second stage transistor further comprises a passivation layer covering said gate, said field plate arranged on said passivation layer overlapping said gate and extending from the edge of the gate towards the drain contact.

A multistage amplifier block, comprising:

• a first stage transistor arranged to provide current gain;
• a second stage transistor having a field plate, said first transistor coupled to said second transistor with said second transistor providing voltage gain,
• wherein said field plate is electrically connected to the gate of said second transistor,
• wherein said second stage transistor comprises a HEMT having a channel layer and a barrier layer, and further comprises a spacer layer on the surface of said barrier layer with said barrier layer sandwiched between said channel and spacer layers, said gate passing through said spacer layer and contacting said barrier layer, and said field plate arranged on the surface of said spacer layer in contact with said gate.

A multistage amplifier block, comprising:

• a first stage transistor arranged to provide current gain;
• a second stage transistor having a field plate, said first transistor coupled to said second transistor with said second transistor providing voltage gain,
• wherein said field plate is electrically connected to the gate of said second transistor,
• wherein said second stage transistor comprises a HEMT having a channel layer and barrier layer, and said gate is gamma shaped and is in contact with said barrier layer, said HEMT further comprising a spacer layer that at least partially covers said gamma gate, said field plate arranged on said spacer layer and at least partially overlapping said gate.

A multi-stage amplifier block, comprising:

• a first stage transistor arranged to provide current gain;
• a second stage transistor having a field plate, said first transistor coupled to said second transistor with said second transistor providing voltage gain,
• wherein said field plate is electrically connected to the gate of said second transistor,
• wherein said second stage transistor comprises a MESFET having a channel layer, and further comprises a spacer layer on the surface of said channel layer, said gate passing through said spacer layer and contacting said barrier layer, and said field plate arranged on the surface of said spacer layer in contact with said gate.

A multi-stage amplifier, comprising:

• a non-field-plate transistor;
• and
• a field-plate transistor having at least one field plate arranged to reduce the electric field strength within said field plate transistor during operation, said nonfield plate transistor connected to said field plate transistor,
• wherein said field plate at least partially overlaps the gate of said field-plate transistor and extends toward the drain of said field-plate transistor.