Complementary Bipolar Semiconductor Device Flat Field Isolation
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Solution Overview
Problem
Current complementary bipolar CMOS technologies face challenges in achieving low-cost, high-performance, and modular integration of bipolar transistors with CMOS processes, particularly due to the complexity and additional process steps required for deep trench isolation and epitaxial collector layers, which impact the high-frequency performance of pnp transistors.
Innovation Solution
The implementation of a complementary bipolar semiconductor device using flat field isolation regions of varying depths to minimize collector resistance and base-collector capacitance, with shallow trenches and CMOS-compatible processes, reducing the need for additional lithographic steps and allowing for cost-effective production of both npn and pnp transistors with enhanced high-frequency properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deep trench isolation and epitaxial collector layers are used, then high-frequency performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent changes the depth parameter of trench isolation from deep to shallow, and modifies the collector structure from epitaxial layers to implanted collectors, thereby reducing device complexity while maintaining high-frequency performance through optimized implantation profiles and shallow trench dimensions
Solution Approach 2:
The patent extracts and eliminates the complex epitaxial collector layer structure, replacing it with simpler implanted collector regions, while retaining the essential function of collector isolation and electrical performance through the shallow trench isolation structure
2Reliability
If deep trench isolation and epitaxial collector layers are used, then high-frequency performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the depth parameter of trench isolation from deep to shallow, and modifies the collector structure from epitaxial layers to implanted collectors, thereby reducing manufacturing cost while maintaining high-frequency performance through optimized implantation profiles and shallow trench dimensions
Solution Approach 2:
The patent replaces expensive epitaxial growth processes with more cost-effective ion implantation and shallow trench isolation techniques, achieving comparable or superior performance at lower manufacturing cost
3Manufacturing precision
If additional lithographic steps are added, then bipolar integration performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the bipolar transistor fabrication steps with the CMOS process flow, combining isolation, collector, and emitter formation into integrated process steps that share lithographic patterns and processing conditions, thereby reducing the number of additional lithographic steps required
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 achieves low collector resistance and base-collector capacitance with minimal additional lithographic steps, enabling cost-effective and high-performance bipolar integration, specifically improving the high-frequency characteristics of both npn and pnp transistors while maintaining CMOS process compatibility.
Implementation Method 1
The high-frequency performance of silicon-based bipolar junction transistors (BJT) has been significantly improved in recent years through the use of a hetero-base layer produced by epitaxy.
Implementation Method 2
a further performance boost for SiGe HBTs is due to the additional incorporation of carbon in the SiGe base layer and/or in adjacent ones
Data Source
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AI summary
Complementary bipolar semiconductor device (Cbi semiconductor device) with a substrate of a first conductivity type, active bipolar transistor regions in the substrate in which the base, emitter, and collector of vertical bipolar transistors are arranged; vertical epitaxial base npn bipolar transistors in a first subset of the active bipolar transistor regions; vertical epitaxial base pnp bipolar transistors in a second subset of the active bipolar transistor regions; collector contact regions which are each arranged bordering on an active bipolar transistor region; and flat field isolation regions which each laterally bound the active bipolar transistor regions and the collector contact regions. A flat field isolation region of a first type with a first extended depth in the direction of the substrate interior is arranged between the first or the second or both the first and the second subset of active bipolar transistor regions on one side and the adjacent collector contact regions on the other, and flat field isolation areas of a second type, with a second extended depth larger than the first, bound the active bipolar transistor regions and the collector contact regions, viewed in cross section, on the sides thereof facing away from each other.