A high electron mobility transistor includes a substrate, a compound semiconductor stacked layer, a cap layer, a gate electrode, a source electrode, a drain electrode, and a buried electrode and/or a conductive structure. The substrate has an active area. The cap layer is disposed on the compound semiconductor stacked layer. The gate electrode is disposed on the cap layer and extends along a first direction. The source electrode and the drain electrode are disposed on the compound semiconductor stacked layer, respectively on two sides of the gate electrode, and arranged along a second direction, where the first direction is perpendicular to the second direction. The conductive structure and/or the buried electrode passes through the compound semiconductor stacked layer and surrounds or lies in the active area, where the conductive structure and/or the buried electrode has a constant electric potential or is grounded.

A method of forming a semiconductor device includes forming active regions, forming S/D regions, forming MD contact structures and forming gate lines resulting in corresponding transistors that define a first time delay circuit having a first input configured to receive a first clock signal and having a first output configured to generate a second clock signal from the first clock signal; and corresponding transistors that define a second time delay circuit having a second input configured to receive the second clock signal and having a second output configured to generate a third clock signal from the first clock signal; forming a first gate via-connector in direct contact with the first gate line atop the first-type active region in the first area; and forming a second gate via-connector in direct contact with the second gate line atop the second-type active region in the second area.

A high electron mobility transistor (HEMT) device includes at least an AlN nucleation layer, a superlattice composite layer, a GaN electron transport layer, and an AlGaN barrier layer. The superlattice composite layer is disposed on the AlN nucleation layer, and the superlattice composite layer includes a plurality of AlN films and a plurality of GaN films stacked alternately to reduce device stress. The GaN electron transport layer is disposed on the superlattice composite layer, and the AlGaN barrier layer is disposed on the GaN electron transport layer.

In one embodiment, a method of fabricating a semiconductor device having an isolated first transistor circuit and an isolated second transistor circuit is provided. The method comprises providing a silicon on insulator (SOI) wafer and fabricating an isolated first silicon region and an isolated second silicon region on the SOI wafer wherein each of the first silicon region and the second silicon region is bounded on its sides by a trench filled with insulator material. The method further comprises fabricating an active area comprising GaN on each of the first silicon region and the second silicon region to form the first transistor circuit and the second transistor circuit and fabricating source, drain, gate, and body connections for each of the first transistor circuit and the second transistor circuit.

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 transistor arrangement includes: a layer stack with first and second semiconductor layers of complementary first and second doping types; a first source region of a first transistor device adjoining the first semiconductor layers; a first drain region of the first transistor device adjoining the second semiconductor layers and spaced apart from the first source region; gate regions of the first transistor device, each gate region adjoining at least one second semiconductor layer, being arranged between the first source region and the first drain region, and being spaced apart from the first source region and the first drain region; a third semiconductor layer adjoining the layer stack and each of the first source region, first drain region, and each gate region; and active regions of a second transistor device integrated in the third semiconductor layer in a second region spaced apart from a first region of the third semiconductor layer.

Apparatus and methods for compound semiconductor protection clamps are provided herein. In certain configurations, a compound semiconductor protection clamp includes a resistor-capacitor (RC) trigger network and a metal-semiconductor field effect transistor (MESFET) clamp. The RC trigger network detects when an ESD/EOS event is present between a first node and a second node, and activates the MESFET clamp in response to detecting the ESD/EOS event. When the MESFET clamp is activated, the MESFET clamp provides a low impedance path between the first and second nodes, thereby providing ESD/EOS protection. When deactivated, the MESFET clamp provides high impedance between the first and second nodes, and thus operates with low leakage current and small static power dissipation.

A high-electron mobility transistor includes a substrate layer, a first buffer layer provided on the substrate layer, a barrier layer provided on the first buffer layer, a source provided on the barrier layer, a drain provided on the barrier layer, and a gate provided on the barrier layer. The transistor further includes a p-type material layer having a length parallel to a surface of the substrate layer over which the first buffer layer is provided, the length of the p-type material layer being less than an entire length of the substrate layer. The p-type material layer is provided in one of the following: the substrate layer, or the first buffer layer. A process of making the high-electron mobility transistor is disclosed as well.

A high electron mobility heterojunction transistor, including a first GaN layer; a second, p-doped GaN layer on top of the first layer, including magnesium as a p-type dopant, the concentration of which is at least equal to 5*10.sup.16 cm.sup.−3 and at most equal to 2*10.sup.18 cm.sup.−3, the thickness of the second GaN layer being between 20 and 50 nm; a third, n-doped GaN layer on top of the second GaN layer in order to form a depleted p-n junction; a fourth GaN layer, which is not intentionally doped, on top of the third GaN layer; a semiconductor layer plumb with the fourth GaN layer, which is not intentionally doped, in order to form an electron gas layer.

A high-electron-mobility field effect transistor is formed with a buffer region having a stepped lateral profile, the stepped lateral profile having first, second and third cross-sections of the buffer region, the first cross-section being thicker than the third cross-section and including a buried field plate, the second cross-section interposed between the first and third cross-sections and forming oblique angles with the first and third cross-sections. A barrier region is formed along the stepped lateral profile. The barrier region is separated from the buried field plate by a portion of the buffer region. The buffer region is formed from a first semiconductor material and the barrier region is formed from a second semiconductor material. The first and second semiconductor materials have different band-gaps such that an electrically conductive channel of a two-dimensional charge carrier gas arises at an interface between the buffer and barrier regions.