A method for activating implanted dopants and repairing damage to dopant-implanted GaN to form n-type or p-type GaN. A GaN substrate is implanted with n- or p-type ions and is subjected to a high-temperature anneal to activate the implanted dopants and to produce planar n- or p-type doped areas within the GaN having an activated dopant concentration of about 10.sup.18-10.sup.22 cm.sup.−3. An initial annealing at a temperature at which the GaN is stable at a predetermined process temperature for a predetermined time can be conducted before the high-temperature anneal. A thermally stable cap can be applied to the GaN substrate to suppress nitrogen evolution from the GaN surface during the high-temperature annealing step. The high-temperature annealing can be conducted under N.sub.2 pressure to increase the stability of the GaN. The annealing can be conducted using laser annealing or rapid thermal annealing (RTA).

A semiconductor device includes a semiconductor substrate configured to include a channel, first and second ohmic contacts supported by the semiconductor substrate, in ohmic contact with the semiconductor substrate, and spaced from one another for current flow between the first and second ohmic contacts through the channel, and first and second dielectric layers supported by the semiconductor substrate. At least one of the first and second ohmic contacts extends through respective openings in the first and second dielectric layers. The second dielectric layer is disposed between the first dielectric layer and a surface of the semiconductor substrate, and the second dielectric layer includes a wet etchable material having an etch selectivity to a dry etchant of the first dielectric layer.

An ohmic contact to a semiconductor layer including a heterostructure barrier layer and a metal layer adjacent to the heterostructure barrier layer is provided. The heterostructure barrier layer can form a two dimensional free carrier gas for the contact at a heterointerface of the heterostructure barrier layer and the semiconductor layer. The metal layer is configured to form a contact with the two dimensional free carrier gas.

A semiconductor device includes a substrate; a first nitride semiconductor layer above the substrate; a second nitride semiconductor layer on the first nitride semiconductor layer; an ohmic electrode above the substrate; and a contact layer in contact with at least a part of the ohmic electrode, the contact layer containing silicon and chlorine. The second nitride semiconductor layer has a wider band gap than the first nitride semiconductor layer. A two-dimensional electron gas channel is formed in the first nitride semiconductor layer at a heterointerface between the first nitride semiconductor layer and the second nitride semiconductor layer. A silicon concentration has a higher peak value than a chlorine concentration in the contact layer.

Disclosed is a method for reducing contact resistance, including depositing a GST layer on an InGaAs substrate, generating an InGaAs/GST/Ni stacked structure by depositing a Ni layer on the GST layer, and thermally treating the stacked structure to rearrange components of the GST layer and to generate a Ni—InGaAs alloy.

A method of forming an integrated circuit employs a plurality of layers formed on a substrate including i) bottom n-type ohmic contact layer, ii) p-type modulation doped quantum well structure (MDQWS) with a p-type charge sheet formed above the bottom n-type ohmic contact layer, iii) n-type MDQWS offset vertically above the p-type MDQWS, and iv) etch stop layer formed above the p-type MDQWS. P-type ions are implanted to define source/drain ion-implanted contact regions of a p-channel HFET which encompass the p-type MDQWS. An etch operation removes layers above the etch stop layer of iv) for the source/drain ion-implanted contact regions using an etchant that automatically stops at the etch stop layer of iv). Another etch operation removes remaining portions of the etch stop layer of iv) to form mesas that define an interface to the source/drain ion-implanted contact regions of the p-channel HFET. Source/Drain electrodes are on such mesas.

A technique of reducing the contact resistance between a semiconductor substrate and a metal layer is provided. A manufacturing method of a semiconductor device comprises a process of forming a metal layer on an N surface of a nitride semiconductor substrate. The process of forming the metal layer includes a first process of forming a metal layer by sputtering at a film formation rate controlled to 4 nm/minute or lower.

A semiconductor device includes a semiconductor substrate configured to include a channel, a gate supported by the semiconductor substrate to control current flow through the channel, a first dielectric layer supported by the semiconductor substrate and including an opening in which the gate is disposed, and a second dielectric layer disposed between the first dielectric layer and a surface of the semiconductor substrate in a first area over the channel. The second dielectric layer is patterned such that the first dielectric layer is disposed on the surface of the semiconductor substrate in a second area over the channel.

A Field Effect Transistor (FET) structure having: a semiconductor; a first electrode structure; a second electrode structure; and a third electrode structure for controlling a flow of carriers in the semiconductor between the first electrode structure and the second electrode structure; a dielectric structure disposed over the semiconductor and extending horizontally between first electrode structure, the second electrode structure and the third electrode structure; and a fourth electrode passing into the dielectric structure and terminating a predetermined, finite distance above the semiconductor for controlling an electric field in the semiconductor under the fourth electrode structure.

A method for preparing an ohmic contact electrode of a GaN-based device. Said method comprises the following steps: growing a first dielectric layer (203) on an upper surface of a device (S1); implanting silicon ions and/or indium ions in a region of the first dielectric layer (203) corresponding to an ohmic contact electrode region, and in the ohmic contact electrode region of the device (S2); growing a second dielectric layer (206) on an upper surface of the first dielectric layer (203) (S3); activating the silicon ions and/or the indium ions by means of a high temperature annealing process, so as to form an N-type heavy doping (S4); respectively removing portions, corresponding to the ohmic contact electrode region, of the first dielectric layer (203) and the second dielectric layer (206) (S5); growing a metal layer (208) on the upper surface of the ohmic contact electrode region of the device, so as to form an ohmic contact electrode (S6). The ohmic contact electrode prepared by the method can ensure that the metal layer (208) has flat surfaces, smooth and regular edges, and said electrode has stable device breakdown voltage, and is reliable and has a long service life.