SOI Transistor Test Structure for Body-Effect Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional silicon-on-insulator (SOI) transistor test structures face difficulties in accurately measuring the body-effect due to the formation of a depletion region, which impedes current flow and results in erroneous threshold voltage measurements and inaccurate body-effect models.
Innovation Solution
The introduction of a second semiconductor body contact that forms a direct electrical contact with the doped halo, eliminating the intermediate lightly doped semiconductor body portion that impedes current flow, allowing for accurate voltage control and measurement of the doped halo.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional SOI transistor test structure with a lightly doped semiconductor body portion is used to measure body-effect, then the structure can be manufactured with standard doping processes, but the depletion region that forms in the lightly doped portion impedes current flow and causes erroneous threshold voltage measurements
Solution Approach 1:
The patent removes the problematic lightly doped semiconductor body portion from the test structure. By directly contacting the heavily doped semiconductor body contact with the doped halo region, it extracts the source of the depletion region problem while maintaining the ability to measure body-effect accurately.
Solution Approach 2:
The patent introduces an intermediate highly doped semiconductor body contact that serves as a mediator between the measurement probe and the doped halo. This highly doped contact acts as an effective intermediary that prevents depletion region formation while allowing accurate voltage control and measurement.
2Reliability
If a heavily doped semiconductor body contact is used to control the voltage of the doped halo, then voltage control is improved, but the doping concentration difference creates a depletion region that impedes current flow
Solution Approach 1:
The patent changes the doping concentration parameter of the semiconductor body contact to be highly doped (comparable to the doped halo) rather than lightly doped. This parameter change eliminates the depletion region formation while maintaining reliable voltage control, as the high doping concentration prevents the formation of depletion regions between the contact and the doped halo.
3Device complexity
If the voltage of the doped halo is measured through a lightly doped semiconductor body portion, then the measurement structure is simple, but the depletion region causes the measured voltage to differ significantly from the applied voltage
Solution Approach 1:
The patent extracts the lightly doped semiconductor body portion that causes measurement errors. By directly contacting the heavily doped semiconductor body contact with the doped halo, it eliminates the intermediate layer that creates depletion regions and voltage measurement discrepancies, resulting in accurate voltage measurements.
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
This approach provides more accurate threshold voltage measurements and improved body-effect models, enhancing the design and fabrication of transistor structures by ensuring the voltage of the doped halo closely matches the applied voltage, thereby increasing measurement accuracy.
Implementation Method 1
current flow between the heavily doped semiconductor body contact and the doped halo region of the semiconductor body can be impeded by a depletion region that can form in the lightly doped semiconductor body portion
Data Source
AI summary
According to one exemplary embodiment, a silicon-on-insulator (SOI) transistor test structure includes a gate situated over a semiconductor body and a doped halo under the gate. The SOI transistor test structure further includes at least two semiconductor body contacts situated on opposing sides of the doped halo, where one or more of the at least two semiconductor body contacts forms a direct electrical contact with the doped halo, thereby increasing current flow to the doped halo to facilitate measuring body-effect in the SOI transistor test structure.