Plasma-based barrier layer removal method for increasing peak transconductance while maintaining on-state resistance and related devices

A transistor device, comprising:

• a semiconductor structure comprising a channel layer and a barrier layer;
• and
• source and drain contacts and a gate therebetween on the semiconductor structure,
• wherein the barrier layer comprises a gate recess including the gate therein, and wherein a surface roughness along a floor of the gate recess is less than about 3 Angstroms (Å).

A transistor device, comprising:

• a semiconductor structure comprising a channel layer and a barrier layer;
• and
• source and drain contacts and a gate therebetween on the semiconductor structure,
• wherein a first portion of the barrier layer extending between the source or drain contact and the gate has a first thickness, a second portion of the barrier layer between the gate and the channel layer has a second thickness and defines a length of the gate between the source and drain contacts, and a ratio of the length of the gate to the second thickness is about 10:1 or less.

A transistor device, comprising:

• a semiconductor structure comprising a channel layer and a barrier layer;
• and
• source and drain contacts and a gate therebetween on the semiconductor structure,
• wherein the barrier layer comprises a gate recess including the gate therein, the gate recess comprises opposing sidewalls and a floor therebetween,
• and wherein edges of the gate recess between the floor and the opposing sidewalls comprise inclined surfaces, and the floor of the gate recess comprises a substantially planar surface that is between the inclined surfaces.

A method of fabricating a transistor device, the method comprising:

• providing a semiconductor structure comprising a channel layer and a barrier layer;
• performing a looped recess process comprising a plurality of loops to define a gate recess in the barrier layer, wherein each of the loops comprises an adsorption process and a desorption process configured to remove a monolayer of the barrier layer;
• and
• forming a gate in the gate recess.