Cap-Layer Schottky Diode Structure for Low Leakage at High Temperature
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Solution Overview
Problem
Traditional Schottky diodes face challenges with high reverse leakage current and increased turn-on voltage, which are exacerbated in high-temperature environments, failing to meet performance requirements.
Innovation Solution
A Schottky diode structure with a cap layer and electrodes arranged to avoid direct contact with the heterostructure layer, utilizing a P-type semiconductor layer and mixed contact modes to balance forward turn-on voltage and reverse leakage, and incorporating a barrier layer to control etching depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a low work function Schottky anode is used to reduce turn-on voltage, then forward conduction is improved, but reverse leakage current increases significantly
Solution Approach 1:
An intrinsic or lightly-doped semiconductor layer is introduced as an intermediary between the metal anode and the heterostructure layer. This intermediate layer acts as a buffer that reduces the direct interaction between the low work function metal and the heterostructure, thereby maintaining low forward turn-on voltage while significantly reducing reverse leakage current by preventing direct Schottky contact that causes high reverse breakdown.
2Reliability
If a high work function anode is used to reduce off-state leakage current and increase reverse withstand voltage, then reverse performance is improved, but turn-on voltage and conduction losses increase significantly
Solution Approach 1:
The semiconductor layer is designed with spatially varying doping characteristics - being intrinsic or lightly-doped in the region directly beneath the metal anode to minimize reverse leakage, while allowing the heterostructure layer to maintain its full functionality in other regions. This local optimization enables low reverse breakdown voltage in the contact region without compromising the overall device performance.
3Device complexity
If the anode layer is directly formed on the heterostructure layer, then device structure is simplified, but leakage characteristics deteriorate in high temperature environments
Solution Approach 1:
The intrinsic or lightly-doped semiconductor layer serves as a thermal buffer and electrical intermediary that becomes particularly effective at high temperatures. This intermediate layer prevents direct thermal runaway between the metal anode and heterostructure layer, maintaining stable leakage characteristics even in high-temperature operating conditions where direct contact would cause significant degradation.
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
Reduces reverse leakage and conduction loss, maintaining low forward turn-on voltage while enhancing reverse withstand voltage, particularly in high-temperature conditions.
Implementation Method 1
a Schottky contact between the electrodes and the cap layer
Implementation Method 2
a P-type semiconductor layer, a doping element of the P-type semiconductor layer including magnesium
Data Source
AI summary
Disclosed are a Schottky diode and a manufacturing method thereof. The Schottky diode includes a substrate, a first semiconductor layer, a heterostructure layer, a passivation layer, and a cap layer stacked in sequence. The passivation layer includes a first groove and a second groove, and the first groove and the second groove penetrate through at least the passivation layer. A first electrode is arranged at least on the cap layer corresponding to the first groove; a second electrode is arranged in the second groove. A Schottky contact is formed between the first electrode and the cap layers, so that a direct contact area between the first electrode and the heterostructure layer may be avoided, a contradiction between the forward turn-on voltage and the reverse leakage of the Schottky diode may be balanced, and a leakage characteristic of the heterostructure layer in a high temperature environment may be suppressed.