Bipolar Junction Transistor Single Deposition Emitter Base
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Solution Overview
Problem
Current methods for manufacturing bipolar junction transistors require a two-stage deposition process to form an epitaxially grown mono-silicon emitter and base portion, which is inefficient and in need of improvement.
Innovation Solution
A single deposition process is employed to form both the epitaxially grown mono-silicon emitter and the base portion of a bipolar junction transistor, using a silicon deposition process that alternates between pure silicon and silicon with impurity materials to create a base layer comprising multiple layers, followed by etching and dielectric layer deposition to define the emitter and base regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-stage deposition process is used to form the epitaxially grown mono-silicon emitter and base portion, then the emitter access resistivity is reduced, but the manufacturing process complexity and time increase
Solution Approach 1:
The patent combines the formation of the base layer and emitter layer into a single continuous deposition process. The emitter layer is formed by depositing additional silicon material over the base layer without interrupting the deposition process, thereby merging two previously separate stages into one unified process that reduces complexity while maintaining the low resistivity benefit
Solution Approach 2:
The single deposition process serves multiple functions: it forms both the base layer and the emitter layer, establishes the epitaxial structure, and controls the doping profile throughout. This multi-functional approach eliminates the need for separate deposition stages while achieving the same electrical performance improvements
2Reliability
If a two-stage deposition process is used to form the epitaxially grown mono-silicon emitter and base portion, then the emitter access resistivity is reduced, but the manufacturing time increases
Solution Approach 1:
The deposition process continues uninterrupted to form both the base and emitter layers. By maintaining continuous deposition without stopping between base and emitter formation, the process eliminates idle time and process transitions, thereby reducing total manufacturing time while still achieving the desired low emitter access resistivity
Solution Approach 2:
The base layer is formed first as a preliminary structure, and the emitter layer is then deposited continuously over it in the same process run. This preliminary formation of the base layer within the same deposition sequence allows the emitter to be created immediately afterward without process interruption, reducing overall manufacturing time
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 manufacturing process and reduces emitter access resistivity by forming both the mono-silicon emitter and base in a single step, enhancing the transistor's performance and efficiency.
Implementation Method 1
a silane deposition process is then employed to deposit silicon over the collector 110 and over the STI structures 120 to form a base layer 130
Implementation Method 2
The deposition process depicted in FIGS. 10 and 11 is believed to be a chemical vapour deposition (CVD) process
Data Source
AI summary
A system and method is disclosed for manufacturing a bipolar junction transistor that comprises an emitter/base layer that is formed by a single deposition process. In one advantageous embodiment of the invention the emitter/base layer comprises an emitter layer that comprises an epitaxially grown mono-silicon emitter. The epitaxially grown mono-silicon emitter significantly reduces the electrical resistivity of the emitter. A non-dopant impurity such as germanium is added to the base layer to endpoint a dry plasma etch process that is applied to etch the emitter/base layer.