Bottom-Side Source-Drain Regrowth After Backend Thermal Exposure
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Solution Overview
Problem
Existing semiconductor contact structures formed during front-end processing are degraded by thermal operations in back-end processing, leading to high contact resistance, which results in poor device performance characterized by low speeds and increased power consumption.
Innovation Solution
The process involves amorphizing and recrystallizing source-drain regions from the bottom-side of a semiconductor assembly using an implant and fast anneal techniques like laser or rapid thermal anneal, achieving a highly active metastable state of dopants that reduces contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact structures are formed during front-end processing operations, then contact structures are initially formed with low contact resistance, but thermal operations during back-end processing degrade the contact structures and increase contact resistance
Solution Approach 1:
The contact structures are formed during front-end processing operations before the thermal operations of back-end processing occur. This preliminary formation allows the contact structures to be created under controlled conditions with low contact resistance, and the sequence of operations is carefully managed to minimize thermal degradation during subsequent processing steps.
Solution Approach 2:
The patent utilizes changes in processing parameters, particularly temperature and timing, to optimize contact structure formation. By controlling the temperature profiles and processing sequences, the contact structures maintain low contact resistance despite exposure to thermal operations during back-end processing.
2Reliability
If high contact resistance occurs, then device performance degrades with low speeds and increased power consumption, but reducing contact resistance requires precise control of dopant activation and crystal structure
Solution Approach 1:
The patent employs phase transitions of dopant atoms between amorphous and crystalline states to achieve high dopant activation. By controlling the crystal structure transitions through thermal processing, the dopant atoms are activated to provide low contact resistance while maintaining precise control over the activation process through managed thermal exposure.
Solution Approach 2:
The patent replaces traditional mechanical or chemical doping methods with a thermal field-based approach using controlled heating and cooling cycles. This thermal field method enables precise control of dopant activation and crystal structure transformation, achieving high dopant activation and low contact resistance through temperature-controlled phase transitions rather than mechanical implantation or chemical diffusion.
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 significantly reduces contact resistance, enhancing device performance by increasing drive current, switching speed, and reducing power consumption.
Implementation Method 1
forming a first implant in the first source-drain region and forming a second implant in the second source-drain region, wherein forming the first implant and forming the second implant causes at least a portion of the first source-drain region and the second source-drain region to change from crystalline to amorphous
Implementation Method 2
performing a thermal anneal causes at least a portion of the first source-drain region and the second source-drain region to recrystallize
Implementation Method 3
fast anneal techniques like laser or rapid thermal anneal
Implementation Method 4
fast anneal techniques like laser or rapid thermal anneal
Data Source
AI summary
A device is disclosed. The device includes a channel, a first source-drain region adjacent a first portion of the channel, the first source-drain region including a first crystalline portion that includes a first region of metastable dopants, a second source-drain region adjacent a second portion of the channel, the second source-drain region including a second crystalline portion that includes a second region of metastable dopants. A gate conductor is on the channel.