SiGe Heterojunction Bipolar Transistor Structure With Single Epitaxy
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Solution Overview
Problem
The manufacturing of heterojunction bipolar transistors requires complex and costly processing steps, such as repetitive epitaxial growth processes and masking processes, which increase production 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
1Manufacturing precision
If multiple epitaxial growth passes and masking processes are used to manufacture heterojunction bipolar transistors, then manufacturing precision and device quality are improved, but device complexity and production cost increase
Solution Approach 1:
The patent combines multiple epitaxial growth processes into a single continuous growth pass, forming the collector, subcollector, intrinsic base, extrinsic base, and emitter regions simultaneously. This merging of processes reduces the total number of processing steps while maintaining the required manufacturing precision through carefully controlled in-situ growth conditions and single-step patterning.
Solution Approach 2:
The single epitaxial growth process performs multiple functions: forming various doped regions (collector, subcollector, base, emitter), creating the heterojunction structure, and establishing the vertical transistor architecture all in one operation. This multi-functional approach eliminates the need for separate masking and growth steps for each layer.
2Manufacturing precision
If multiple epitaxial growth passes and masking processes are used to manufacture heterojunction bipolar transistors, then manufacturing precision and device quality are improved, but production cost increases
Solution Approach 1:
The patent combines multiple epitaxial growth passes into a single growth operation, reducing the cumulative cost of equipment usage, materials, and processing time. By forming all necessary regions in one continuous process, the patent eliminates repeated setup, heating, and cooling cycles that would otherwise increase production costs.
Solution Approach 2:
The patent eliminates the need for intermediate masking layers and removal steps between growth passes. By using a single growth process with in-situ doping, the patent discards the expensive and time-consuming masking/unmasking cycle while recovering the costs through reduced material consumption and shorter processing times.
3Manufacturing precision
If multiple epitaxial growth passes are used to manufacture heterojunction bipolar transistors, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The patent merges multiple sequential epitaxial growth operations into a single continuous growth process, eliminating the time required for intermediate cooling, heating, and chamber preparation between passes. The single pass approach maintains precision through controlled growth conditions while dramatically reducing total fabrication time.
Solution Approach 2:
The patent maintains continuous epitaxial growth throughout the formation of all transistor regions without interrupting the growth process. This continuity eliminates idle time between processing steps while maintaining manufacturing precision through consistent growth conditions throughout the entire structure formation.
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 production costs and simplifies the fabrication process while maintaining the quality of the semiconductor structures, enabling efficient manufacturing 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
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AI summary
A structure comprising, a collector, a subcollector, 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 and/or a hardmask between the collector and the extrinsic base.