Varactor Hyper-Abrupt Junction Superlattice Structure
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Solution Overview
Problem
Current semiconductor devices do not fully leverage advanced materials and processing techniques to achieve optimal performance in terms of charge carrier mobility and device efficiency.
Innovation Solution
The development of a semiconductor device with a hyper-abrupt junction region that includes a superlattice layer, comprising stacked groups of semiconductor and non-semiconductor monolayers, which reduces the effective mass of charge carriers and enhances mobility by forming a barrier to dopant and material diffusion, thereby improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional semiconductor structures are used, then manufacturing is simpler, but charge carrier mobility is insufficient
Solution Approach 1:
The semiconductor structure is divided into multiple thin monolayer layers (first semiconductor layer, superlattice layer, second semiconductor layer) with distinct functions. The superlattice layer itself is segmented into repeating units of semiconductor and non-semiconductor monolayers, creating a segmented structure that enhances charge carrier mobility through reduced effective mass while maintaining manufacturability through epitaxial growth processes.
Solution Approach 2:
The invention employs composite material structures including the superlattice layer composed of alternating semiconductor and non-semiconductor monolayers. This composite structure combines materials with different properties to achieve enhanced charge carrier mobility and controlled dopant diffusion barriers, resolving the contradiction between performance and complexity.
2Reliability
If dopant diffusion is allowed, then manufacturing is easier, but device performance degrades due to unwanted scattering
Solution Approach 1:
The superlattice layer acts as an intermediary barrier between the first and second semiconductor layers. Its composite structure of semiconductor and non-semiconductor monolayers provides a controlled interface that prevents unwanted dopant diffusion and material mixing, thereby maintaining device performance without requiring complex manufacturing processes.
Solution Approach 2:
The superlattice layer introduces local quality variations through its alternating monolayer structure. Different regions of the superlattice (semiconductor vs. non-semiconductor monolayers) provide different local properties: charge transport pathways and dopant diffusion barriers, respectively. This local differentiation enhances overall device performance while using standard epitaxial manufacturing techniques.
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
The superlattice structure enhances charge carrier mobility and provides a barrier to unwanted scattering effects, leading to improved device performance and potential applications in opto-electronic devices with direct energy bandgap advantages.
Implementation Method 1
The resulting biaxial strain in the upper silicon layer alters the carrier mobilities enabling higher speed and/or lower power devices
Implementation Method 2
enhances mobility by forming a barrier to dopant and material diffusion
Implementation Method 3
a superlattice in which a plurality of layers, less than eight monolayers, and containing a fractional or binary or a binary compound semiconductor layer, are alternately and epitaxially grown
Implementation Method 4
alternately and epitaxially grown
Data Source
AI summary
A method for making a semiconductor device may include forming a hyper-abrupt junction region on a substrate. The hyper-abrupt junction region may include a first semiconductor layer having a first conductivity type, a superlattice layer on the first semiconductor layer, and a second semiconductor layer on the superlattice layer and having a second conductivity type different than the first conductivity type. The superlattice may include stacked groups of layers, with each group of layers including stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The method may further include forming a first contact coupled to the hyper-abrupt junction regions, and forming a second contact coupled to the substrate to define a varactor.