Vertical Bipolar Transistor Layout for SOI Isolation and Low Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of vertical bipolar transistors in semiconductor-on-insulator (SOI) substrates is complex and costly, with challenges in adjacent device isolation and leakage, which increases process complexity and requires additional processing steps.
Innovation Solution
The vertical bipolar transistors are fabricated with a collector region confined within a buried insulator layer, featuring a tunable base width and reduced base-to-collector capacitance, utilizing semiconductor-on-insulator material and epitaxial growth processes to form intrinsic and extrinsic base regions, and a collector contact extending vertically from the intrinsic base region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vertical bipolar transistors are formed in bulk substrate or cavity touching handle wafer, then device performance is improved, but cost and process complexity increase
Solution Approach 1:
The patent introduces a buried insulator layer as an intermediary between the collector region and the handle wafer. This mediator enables the transistor to be formed on SOI substrate while achieving performance comparable to bulk substrate devices, thus resolving the contradiction between device performance and process complexity
Solution Approach 2:
The patent transitions from traditional lateral transistor architecture to vertical architecture, changing the dimensional arrangement of components. This vertical configuration allows the transistor to achieve high performance on SOI substrate without requiring complex cavity structures, reducing process complexity while maintaining reliability
2Reliability
If vertical bipolar transistors are formed in bulk substrate, then device performance is improved, but adjacent device isolation and leakage problems arise
Solution Approach 1:
The buried insulator layer serves as an intermediary that electrically isolates the collector region from the handle wafer and adjacent devices. This mediator eliminates leakage paths between adjacent devices while maintaining the performance benefits of vertical transistor architecture
Solution Approach 2:
The patent extracts the collector region from direct contact with the bulk substrate and confines it within the buried insulator layer. This extraction removes the source of leakage and isolation problems associated with bulk substrate fabrication, enabling reliable adjacent device operation
3Object-affected harmful factors
If additional processing steps are added for isolation, then adjacent device isolation is improved, but process complexity increases
Solution Approach 1:
The patent merges the isolation function into the buried insulator layer that is already part of the SOI substrate structure. By combining the isolation layer with the substrate architecture, the patent eliminates the need for separate isolation processing steps, thus improving isolation without increasing process complexity
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 simplifies the fabrication process by eliminating masking steps and implant/anneal processes, reducing process complexity and achieving improved device performance with reduced base-to-collector capacitance.
Implementation Method 1
utilizing semiconductor-on-insulator material and epitaxial growth processes to form intrinsic and extrinsic base regions, and a collector contact extending vertically from the intrinsic base region
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to vertical bipolar transistors and methods of manufacture. The structure includes: an intrinsic base region comprising semiconductor-on-insulator material; a collector region confined within an insulator layer beneath the semiconductor-on-insulator material; an emitter region above the intrinsic base region; and an extrinsic base region above the intrinsic base region.