Indian Institute of Science

General Electric Company

Srinivasan Raghavan

Mayank Shrivastava

Navakanta Bhat

Ankit Soni

Rohith Soman

Arthur Samuel Peck

Shan Liu

Warren Tan King

Dayananda Narayana

Sayak Dutta Gupta

Hareesh Chandrasekar

Nagaboopathy Mohan

Navakant Bhat

Dhayalan Shakthivel

The present subject matter provides a High Mobility Electron Transistor (HEMT) comprising: a substrate, a nucleation layer provided on the substrate, a channel layer, and a buffer layer formed between the nucleation layer and the channel layer. The buffer layer comprises a vertical stack of p-n junctions. Each p-n junction of the vertical stack of p-n junctions comprises an n-type layer provided on a p-type layer. The n-type layer and the p-type layer are parallel to the substrate.

Stacked buffer in transistors

A High Electron Mobility Transistor (HEMT) having a reduced surface field (RESURF) junction is provided. The HEMT includes a source electrode at a first end and a drain electrode at a second end. A gate electrode is provided between the source electrode and the drain electrode. A reduced surface field (RESURF) junction extends from the first end to the second end. The gate electrode is provided above the RESURF junction. A buried channel layer is formed in the RESURF junction on application of a positive voltage at the gate electrode. The RESURF junction includes an n-type Gallium nitride (GaN) layer and a p-type GaN layer. The n-type GaN layer is provided between the p-type GaN layer and the gate electrode.

High electron mobility transistor (HEMT) with RESURF junction

The present invention provides a metal nitride platform for semiconductor devices, including, a pre-defined array of catalyst sites, disposed on a substrate. Metal nitride islands with lateral to vertical size ratios of at least greater than one (1) are disposed on the array of catalyst sites, where the surfaces of the metal nitride islands are with reduced dislocation densities and side walls with bending of dislocations. The platform of metal nitride islands is further used to build electrically and optically-active devices. The present invention also provides a process for the preparation of a metal nitride platform, selectively, on the array of catalyst sites, in the presence of a reactive gas and precursors and under preferred reaction conditions, to grow metal nitride islands with lateral to vertical size ratios of at least greater than one (1).

Platform of large metal nitride islands with lateral orientations and low-defect density

The present disclosure provides an improved enhancement mode field effect transistor (FET) having an oxide (AlTiO) emulating p-type gate. The present disclosure provides a novel enhancement mode High Electron Mobility Transistor (HEMT) structure with AlTiO Gate Oxide Engineering as Replacement of p-GaN Gate. In an aspect, the present disclosure provides a hybrid gate stack that combines p-GaN technology with the proposed oxide for e-mode operation. The HEMT structure with AlTiO Gate oxide provides a threshold voltage tuning from negative to positive by changing p-doping composition. Using a developed p-type oxide, e-mode device shows ON current &#x2dc;400 mA/mm, sub-threshold slope of 73 mV/dec, R=8.9 &#x3a9;mm, interface trap density &#x3c;10mmeVand gate leakage below 200 nA/mm at the OFF-state breakdown.

Enhancement mode high electron mobility transistor (HEMT)

A grain starter for use in solidification of molten metallic material forming an article having a directional grain structure and a method for solidifying an article having a directional grain structure with a substantial absence of stray grains. The grain starter comprises a grain-starting material that initiates grain growth in the molten metallic material in a preselected crystallographic direction. The grain-starting material has a melting temperature higher than the metallic material forming the article lest the grain starter be modified by contact with the molten material. The grain starter further includes a feature that modifies heat transfer characteristics of the metallic material in contact with it in order to produce an article having grains oriented in the preselected crystallographic orientation and modifies the profile of the advancing solidification front. The article is substantially free of stray grains not oriented in the preselected crystallographic direction.

Composite geometrical design for a grain starter in a bridgman investment casting process

Growing community of inventors

Bengaluru, India

Srinivasan Raghavan