Avalanche Diode Defect Concentration for ESD Protection
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Solution Overview
Problem
Integrated circuits and semiconductor devices are vulnerable to damage from electrostatic discharge (ESD) and electrical overstress (EOS), leading to reliability issues due to delayed avalanche breakdown phenomena during short ESD pulses, which can result in circuit failures.
Innovation Solution
An avalanche diode with an enhanced defect concentration level in the avalanche ignition region, created by ion implantation of a second atomic species, provides rapid onset of avalanche breakdown when a reverse-bias voltage exceeds the diode breakdown voltage, ensuring fast turn-on and effective ESD/EOS protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional avalanche diodes are used without enhanced defect concentration, then the device structure remains simple and manufacturing is easier, but the avalanche breakdown turns on delayed during short ESD pulses, leading to circuit damage
Solution Approach 1:
The patent applies local quality by creating an avalanche ignition region with enhanced defect concentration specifically at the p-n junction area, while keeping other regions of the diode structurally simple. This localized defect enhancement (through ion implantation or epitaxial growth) provides rapid avalanche turn-on exactly where needed during ESD events, without complicating the overall device structure or manufacturing process
2Reliability
If the avalanche diode uses standard defect concentration levels, then manufacturing processes are simpler, but the breakdown voltage increases during short ESD pulses (inhibited avalanche breakdown), causing voltages 10-15 volts higher than DC breakdown values
Solution Approach 1:
The patent changes the defect concentration parameter locally in the avalanche ignition region to enhance avalanche breakdown speed. By controlling defect density (through ion implantation doses or epitaxial growth conditions) specifically in the junction region, the device maintains stable breakdown voltage during short ESD pulses, preventing the 10-15 volt increase that occurs in conventional diodes
3Speed
If conventional diode structures are used, then the response time during ESD pulses is slower, but the device requires fewer processing steps and has lower manufacturing complexity
Solution Approach 1:
The patent applies preliminary action by pre-introducing defects into the avalanche ignition region during manufacturing (via ion implantation or controlled epitaxial growth). These pre-placed defects act as avalanche initiation sites that trigger rapid breakdown immediately when ESD voltage exceeds the breakdown threshold, achieving fast response without adding complex external circuitry or multiple processing stages
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 solution enables reliable and fast turn-on of avalanche breakdown, effectively preventing circuit damage from ESD/EOS events by ensuring immediate onset of avalanche current, thus enhancing the protection of integrated circuits and semiconductor devices.
Implementation Method 1
The avalanche ignition region provides reliable and fast turn-on of avalanche breakdown when a reverse-bias voltage is applied to the diode that exceeds the diode breakdown voltage
Implementation Method 2
the avalanche ignition region is created by placement therein of a second atomic specie that is different from the atomic specie forming the principal diode crystal structure. In an advantageous embodiment, the second atomic specie is placed by ion implantation
Data Source
AI summary
The invention relates to an avalanche diode that can be employed as an ESD protection device. An avalanche ignition region is formed at the p-n junction of the diode and includes an enhanced defect concentration level to provide rapid onset of avalanche current. The avalanche ignition region is preferably formed wider than the diode depletion zone, and is preferably created by placement, preferably by ion implantation, of an atomic specie different from that of the principal device structure. The doping concentration of the placed atomic specie should be sufficiently high to ensure substantially immediate onset of avalanche current when the diode breakdown voltage is exceeded. The new atomic specie preferably comprises argon or nitrogen, but other atomic species can be employed. However, other means of increasing a defect concentration level in the diode depletion zone, such as an altered annealing program, are also contemplated.