Self-Aligned SiGe HBT Structure With Single-Pass Epitaxy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of heterojunction bipolar transistors requires complex and costly processing steps, including repetitive epitaxial growth processes, which increase unwanted costs and complexity.
Innovation Solution
The heterojunction bipolar transistors are manufactured using a single epitaxial growth process to form a subcollector, intrinsic base, extrinsic base, and emitter, with an isolation structure between the extrinsic base and emitter that overlaps the subcollector, reducing the number of epitaxial growth passes and mask counts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple epitaxial growth passes and masking processes are used to manufacture heterojunction bipolar transistors, then the structural integrity and performance of the transistors can be maintained, but the manufacturing cost and process complexity increase significantly
Solution Approach 1:
The patent combines multiple epitaxial growth steps into a single continuous growth process. The collector, subcollector, intrinsic base, extrinsic base, and emitter are all formed in one epitaxial pass using in-situ doping, eliminating the need for separate growth cycles and intermediate processing steps that would otherwise be required to achieve the same multi-layer structure.
Solution Approach 2:
The single epitaxial growth process serves multiple functions simultaneously: it forms all the semiconductor layers (collector, subcollector, base regions, emitter), introduces appropriate doping profiles through in-situ doping, and creates the heterojunction structures. This multi-functional approach replaces what would traditionally require multiple specialized processing steps.
2Manufacturing precision
If traditional multi-step epitaxial growth and masking processes are used, then precise layer formation is achieved, but the manufacturing cost increases due to repetitive processing steps
Solution Approach 1:
The patent merges multiple discrete epitaxial growth operations into one continuous process. By performing all layer formations and doping steps in a single epitaxial pass, the method eliminates repetitive processing cycles, reduces the number of mask applications required, and decreases overall manufacturing time and cost while preserving precise layer formation through controlled in-situ doping.
3Manufacturing precision
If multiple masking processes are applied during fabrication, then precise patterning is achieved, but the production time and process repetition increase leading to additional costs
Solution Approach 1:
The patent combines multiple patterning and growth operations into a single epitaxial growth process with in-situ doping. This approach maintains patterning precision by using the doping profile to define regions, while simultaneously reducing the number of separate masking and growth steps, thereby improving production efficiency and reducing process repetition.
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 lowers manufacturing costs and simplifies the process while maintaining the necessary structural integrity and performance of the transistors, enabling efficient production of self-aligned SiGe vertical heterojunction bipolar transistors.
Implementation Method 1
forming in a single epitaxial growth processing pass: a collector in a semiconductor substrate; a subcollector in the semiconductor substrate; an intrinsic base over the subcollector; an extrinsic base adjacent to the intrinsic base; and an emitter over the intrinsic base
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes: a collector in a semiconductor substrate; a subcollector in the semiconductor substrate; an intrinsic base over the subcollector; an extrinsic base adjacent to the intrinsic base; an emitter over the intrinsic base; and an isolation structure between the extrinsic base and the emitter and which overlaps the subcollector.