Nitride Semiconductor Clamp Diode for Surge Resistance
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Solution Overview
Problem
Nitride semiconductor elements using GaN face challenges in handling surge voltages due to high contact resistivity of p-type semiconductor layers, limiting their ability to flow large avalanche currents and thus providing low surge power capacity.
Innovation Solution
A semiconductor device with a p-barrier layer formed between anode and cathode electrodes, which is depleted under high voltage, allowing current flow and clamping voltage, thereby enhancing surge resistance by bypassing contact resistivity constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a p-type semiconductor layer is used in a nitride semiconductor element, then the element structure is simplified, but the contact resistivity increases and surge resistance decreases
Solution Approach 1:
The device is segmented into two functional parts: a clamp diode for surge protection and a power element for normal operation. The clamp diode includes a first semiconductor layer and a second semiconductor layer with opposite conductivity types, forming a dedicated surge protection path that operates independently from the power element, thereby resolving the conflict between simplified structure and surge resistance
Solution Approach 2:
A clamp diode is introduced as an intermediary component between the power element and the surge voltage. This clamp diode with its p-n junction structure acts as a mediator that handles surge currents separately, allowing the main power element to maintain its simple structure while the intermediary component provides the necessary surge protection function
2Strength
If avalanche breakdown occurs in a nitride semiconductor element with p-type layer, then high voltage can be held, but large avalanche current cannot flow due to high contact resistivity
Solution Approach 1:
The current path is segmented into two separate paths: one for normal operation through the power element and another for avalanche current through the clamp diode. The clamp diode is specifically designed with a p-n junction that enables large avalanche current flow without being constrained by the high contact resistivity of p-type layers in the power element
Solution Approach 2:
The conductivity type distribution is changed in the clamp diode region, creating a p-n junction structure with opposite conductivity types in the first and second semiconductor layers. This parameter change enables the clamp diode to support large avalanche currents while the power element maintains its original structure for normal operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device functions as a clamp diode, effectively consuming surge power and providing high surge resistance by allowing large current flow during high voltage applications, similar to avalanche breakdown, without being constrained by p-type contact resistivity.
Implementation Method 1
a p-barrier layer which is depleted when a high voltage is applied
Implementation Method 2
effectively consuming surge power and providing high surge resistance by allowing large current flow during high voltage applications
Data Source
AI summary
A semiconductor device includes: a first semiconductor layer made of an AlxGa1−xN (0≦×<1); a second semiconductor layer provided on the first semiconductor layer and made of an undoped or first conductivity type AlyGa1−yN (0<y≦1, x<y); an anode electrode and a cathode electrode which are connected to the second semiconductor layer; and a third semiconductor layer of second conductivity type provided between the anode electrode and the cathode electrode when viewed from a direction perpendicular to an upper surface of the second semiconductor layer. The third semiconductor layer is depleted when a predetermined magnitude or more of voltage is applied between the anode electrode and the cathode electrode.