Ultra high voltage GaN ESD protection device
AssigneeNational Semiconductor Corporation
InventorVladislav Vashchenko
Life of this patent
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Abstract
In an ultra high voltage lateral GaN structure having a 2DEG region extending between two terminals, an isolation region is provided between the two terminals to provide for reversible snapback.
Claims15
A GaN ESD protection device consisting of
- a first terminal with an ohmic contact or Schottky contact,
- a second terminal with an ohmic contact or Schottky contact,
- a 2D electron gas (2DEG) region between the two terminals,
- a GaN channel region and an AlGaN cap layer formed over the GaN channel region, the 2DEG region being defined by the junction between the GaN channel region and the AlGaN cap layer,
- an AlGaN buffer region below the GaN channel region, and
- an isolation region formed between and around the two terminals, the isolation region is configured to form a ballast region extending laterally from the first terminal and terminating on the isolation region between the two terminals, the isolation region vertically extending from above the top of the 2D electron gas (2DEG) region down through the 2D electron gas (2DEG) region and the GaN channel region touching and terminating at the AlGaN buffer region, wherein the length of the isolation region is configured to control the breakdown and triggering voltages of the ESD device and the ballasting region is configured to provide uniform current density distribution through the ESD device and to move the high electric field and heat generation away from the contacts, wherein the length of the ballast region is longer than the isolation region length.
The device of 5, wherein the GaN channel region between the first terminal and the isolation region is longer than the length of the isolation region.
A method of controlling the breakdown and triggering voltage of a high voltage GaN ESD protection structure that consists of a pair of terminals with ohmic or Schottky contacts connected to a 2DEG region, the method comprising, providing an isolation region between the terminals and extending vertically through the 2DEG region and the GaN channel region touching and terminating at the AlGaN buffer region, by varying the breakdown and triggering voltage of the device by varying the lateral length of the isolation region between the terminals,
- forming an AlGaN ballasting region below the GaN channel region,
- dimensioning the GaN channel region to be long enough to define a ballasting region between one of the terminals and the isolation region to provide for greater uniformity of the current density distribution and to move the high electric field and heat generation away from the terminals,
- wherein the length of the isolation region controls the breakdown and triggering voltages of the ESD device and the length of the ballast region is longer than the isolation region length.
A grid voltage GaN structure that consists of
- a pair of terminals with ohmic or Schottky contacts,
- a 2DEG region, defined by the junction between a GaN layer and an AlGaN layer, extending between the terminals,
- a vertically extending isolation region formed between the terminals that extends through the 2DEG and the GaN channel region touching and terminating at the AlGaN buffer region, and
- a ballast region defined by at least one of the GaN layer and the AlGaN layer extending between the one terminal and the isolation region, the ballast region being longer than the isolation region, wherein the length of the isolation region is configured to control the breakdown and triggering voltages of an ESD device and the ballast region is configured to provide uniform current density distribution through the ESD device and to move the high electric field and heat generation away from the contacts, wherein the length of the ballast region is longer than the isolation region length.
Dependencies are inferred from the claim text.