Semiconductor devices including implanted regions and protective layers

A transistor device comprising:

• a Group III-nitride semiconductor layer including source and drain regions;
• a SiN protective layer on the Group III-nitride semiconductor layer;
• source and drain ohmic contacts extending through the SiN protective layer to contact the source and drain regions, respectively, of the Group III-nitride semiconductor layer;
• and
• a distribution of implanted silicon dopants within the source and drain regions of the Group III-nitride semiconductor layer, wherein the distribution of implanted silicon dopants has a peak concentration at an interface of the Group III-nitride semiconductor layer and the source and drain ohmic contacts.

A semiconductor structure comprising:

• a Group III-nitride semiconductor layer;
• a dielectric protective layer on the Group III-nitride semiconductor layer, the dielectric protective layer having at least one window therein exposing a portion of the Group III-nitride semiconductor layer;
• an ohmic contact extending through the window in the dielectric protective layer to contact the Group III-nitride semiconductor layer;
• and
• a distribution of implanted silicon dopants within the Group III-nitride semiconductor layer, wherein the distribution of implanted silicon dopants has a peak concentration of 1×1018 cm−3 or greater at an interface of the Group III-nitride semiconductor layer and the ohmic contact.