Regrown Heterojunction Bipolar Transistors for Multi-Function Integration
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Solution Overview
Problem
Current methods for collector doping in compound semiconductor HBT devices require multiple substrates, leading to inefficiencies and parasitic effects, making it challenging to integrate multiple HBT devices with different doping profiles on a single chip for multi-function integrated circuits.
Innovation Solution
A method for fabricating integrated devices with multiple HBT devices on a single substrate by depositing and etching collector layers with varying thicknesses and doping levels on separate regions, allowing for the growth of HBT devices with distinct characteristics such as high breakdown voltage and high speed performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple substrates are used to grow HBT devices with different collector doping profiles, then different doping profiles can be achieved, but additional parasitic effects and inter-chip routing occur
Solution Approach 1:
The patent combines multiple HBT devices with different collector doping profiles onto a single substrate by performing selective regrowth on different regions. This merging approach eliminates the need for multiple separate substrates, thereby reducing inter-chip routing and parasitic effects while maintaining the ability to achieve different doping profiles through localized processing
Solution Approach 2:
The patent applies local quality by performing selective regrowth with different doping profiles on specific regions of the same substrate. By using masking techniques and controlled epitaxial growth, each region can have customized collector doping characteristics while the overall device structure remains integrated on a single chip
2Adaptability or versatility
If ion implantation process is used for collector doping of compound semiconductor HBT devices, then different doping profiles can be achieved, but technical issues prevent its general use
Solution Approach 1:
The patent changes the doping method from ion implantation to in-situ doped epitaxial regrowth. This parameter change in the doping process enables better compatibility with compound semiconductor materials while maintaining the ability to achieve different doping profiles through controlled in-situ doping during the regrowth phase
3Ease of manufacture
If epitaxial growth process is used for collector doping, then HBT devices can be grown, but only a single collector doping profile can be achieved on a single substrate
Solution Approach 1:
The patent segments the substrate into different regions that undergo selective regrowth processes. By dividing the single substrate into multiple processing zones with different masking patterns and regrowth conditions, the system maintains the simplicity of epitaxial growth while achieving multiple collector doping profiles across different segments of the same chip
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
Enables the integration of multiple HBT devices with different semiconducting properties on a single chip, reducing inter-chip routing and area requirements, while maintaining uniform thickness across devices for improved performance and reduced process errors.
Implementation Method 1
the collector doping of HBT devices may be performed by an epitaxial growth process
Implementation Method 2
etching the first collector layer above the second region of the substrate
Data Source
AI summary
The present invention may provide an integrated device, which may include a substrate having first and second regions, the first region spaced apart from the second region, a first heterojunction bipolar transistor (HBT) device formed on the first region of the substrate, the first HBT device having a first collector layer formed above the first region of the substrate, the first collector layer having a first collector thickness and a first collector doping level, and a second HBT device formed on the second region of the substrate, the second HBT device having a second collector layer formed above the second region of the substrate, the second collector layer having a second collector thickness and a second collector doping level, the second collector thickness substantially greater than the first collector thickness, the second collector doping level lower than the first collector doping level.