A high electron mobility transistor device including a channel layer, a first barrier layer, a gate structure, and a spacer is provided. The first barrier layer is disposed on the channel layer. The gate structure is disposed on the first barrier layer. The gate structure includes a first P-type gallium nitride layer, a second barrier layer, and a second P-type gallium nitride layer. The first P-type gallium nitride layer is disposed on the first barrier layer. The second barrier layer is disposed on the first P-type gallium nitride layer. The second P-type gallium nitride layer is disposed on the second barrier layer. A width of the second P-type gallium nitride layer is smaller than a width of the first P-type gallium nitride layer. The spacer is disposed on a sidewall of the second P-type gallium nitride layer.

A method for manufacturing an optical device includes providing a carrier waver, provide a first substrate having a first surface region, and forming a first gallium and nitrogen containing epitaxial material overlying the first surface region. The first epitaxial material includes a first release material overlying the first substrate. The method also includes patterning the first epitaxial material to form a plurality of first dice arranged in an array; forming a first interface region overlying the first epitaxial material; bonding the first interface region of at least a fraction of the plurality of first dice to the carrier wafer to form bonded structures; releasing the bonded structures to transfer a first plurality of dice to the carrier wafer, the first plurality of dice transferred to the carrier wafer forming mesa regions on the carrier wafer; and forming an optical waveguide in each of the mesa regions, the optical waveguide configured as a cavity to form a laser diode of the electromagnetic radiation.

A semiconductor device includes a substrate, a back-barrier layer, a channel layer that has a band gap smaller than a band gap of the back-barrier layer, a first barrier layer that has a band gap larger than the band gap of the channel layer, a second barrier layer that is provided to fill a first recessed portion and has a band gap larger than the band gap of the channel layer, a source electrode, a drain electrode, and a gate electrode. An In composition ratio of the first barrier layer is greater than or equal to 0 and less than an In composition ratio of the second barrier layer. An Al composition ratio of the first barrier layer is greater than or equal to an Al composition ratio of the second barrier layer.

Electronic devices are formed on donor substrates and transferred to carrier substrates by forming bonding regions on the electronic devices and bonding the bonding regions to a carrier substrate. The transfer process may include forming anchors and removing sacrificial regions.

A method for manufacturing an optical device includes providing a carrier waver, provide a first substrate having a first surface region, and forming a first gallium and nitrogen containing epitaxial material overlying the first surface region. The first epitaxial material includes a first release material overlying the first substrate. The method also includes patterning the first epitaxial material to form a plurality of first dice arranged in an array; forming a first interface region overlying the first epitaxial material; bonding the first interface region of at least a fraction of the plurality of first dice to the carrier wafer to form bonded structures; releasing the bonded structures to transfer a first plurality of dice to the carrier wafer, the first plurality of dice transferred to the carrier wafer forming mesa regions on the carrier wafer; and forming an optical waveguide in each of the mesa regions, the optical waveguide configured as a cavity to form a laser diode of the electromagnetic radiation.

We provide a fabrication process for III-nitride devices. An iridium structure is deposited and then oxidized at high temperature (700 C. or more) to form an iridium oxide Schottky contact to a III-nitride. This IrO.sub.x contact is then protected with a passivation structure. Such contacts have various device applications, such as forming Schottky diodes and acting as a gate in a transistor or 2D electron gas structure.