Semiconductor Electric Field Observation via Laser Scanning and Voltage Control
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Solution Overview
Problem
Current methods fail to accurately identify electric field concentration points in semiconductor devices, which can lead to damage and reduced withstand voltage performance, as they are difficult to detect without causing damage to the device during measurement.
Innovation Solution
An apparatus and method using a laser light source, voltage application, and detection unit to gradually increase voltage until avalanche amplification occurs, allowing for visualization of electric field concentration points through optical beam induced current imaging, thereby identifying these points without causing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electric field intensity distribution is estimated by calculation and simulation, then the measurement process is non-invasive, but the accuracy of identifying electric field concentration parts is insufficient
Solution Approach 1:
The patent introduces OBIC (optical beam induced current) as an intermediary measurement method. By irradiating the semiconductor device with optical beams and measuring the generated current, the electric field distribution is indirectly detected through the electrical response, enabling accurate identification of concentration parts without direct electrical measurement that would cause damage
Solution Approach 2:
The patent replaces direct electrical measurement methods with optical measurement methods. Instead of using electrical probes that would cause damage, the system uses optical beams to induce current and measure the electrical response, substituting a non-contact optical measurement system for a contact-based electrical measurement system
2Measurement precision
If a semiconductor device with electric field concentration is examined, then the actual electric field concentration can be observed, but the device is severely damaged and the part cannot be identified
Solution Approach 1:
The patent applies partial action by using low-intensity optical beams that generate sufficient OBIC signal for detection without causing damage. The optical beam intensity is carefully controlled to be just sufficient for measurement, avoiding excessive energy input that would cause avalanche breakdown and device damage
Solution Approach 2:
The patent uses OBIC measurement as an intermediary that allows observation of electric field concentration without direct electrical probing. The optical beam serves as a mediator that induces current in a non-destructive manner, enabling measurement of the electric field distribution without causing the severe damage that would occur with direct electrical measurement
3Measurement precision
If voltage is increased to cause avalanche amplification for observation, then electric field concentration parts become visible, but the device may suffer avalanche breakdown and damage
Solution Approach 1:
The patent applies partial action by increasing voltage only to the extent necessary to achieve avalanche amplification for observation, but stopping before reaching the breakdown point. The voltage is carefully controlled to be sufficient for OBIC signal generation and concentration part visibility, yet remains below the threshold that would cause permanent device damage
Solution Approach 2:
The patent employs feedback control in the measurement process. The voltage is gradually increased while monitoring the OBIC signal and electrical response, allowing real-time adjustment to maintain the voltage at the optimal level for observation without exceeding the breakdown threshold. This feedback mechanism ensures device integrity throughout the measurement
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
Accurately identifies electric field concentration points in semiconductor devices while preventing avalanche breakdown, thus enhancing withstand voltage performance and reducing device damage.
Implementation Method 1
a back surface of a silicon semiconductor device is irradiated with YAG laser light with a wavelength of 1064 nm or HeNe laser light with a wavelength of 1152 nm, and the OBIC current is measured
Implementation Method 2
the voltage application unit gradually increases a magnitude of the predetermined voltage until the predetermined voltage reaches a voltage at which avalanche amplification occurs in the semiconductor device
Data Source
AI summary
An observation apparatus includes a laser light source, a scanning optical system irradiating a semiconductor device with laser light output from the laser light source, a bias power supply applying a reverse bias voltage of a predetermined voltage between electrodes of the semiconductor device, a sensor detecting an electrical property occurring in the semiconductor device in response to the laser light, and a control system generating an electrical property image of the semiconductor device based on a detection signal from the sensor. The bias power supply gradually increases a magnitude of the predetermined voltage until the predetermined voltage reaches a voltage at which avalanche amplification occurs in the semiconductor device. When the predetermined voltage is increased, the scanning optical system irradiates with the laser light, the sensor detects the electrical property, and the control system generates the electrical property image.