Semiconductor Annealing for Stable Doping and Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor device manufacturing methods face challenges in achieving consistent doping concentration distributions, particularly due to variations in oxygen chemical concentration and thermal donor formation, which affect the breakdown voltage and overall device performance.
Innovation Solution
The proposed solution involves controlling the thermal history of the semiconductor substrate during annealing to suppress the formation of thermal donors, thereby maintaining a consistent doping concentration distribution. This is achieved by limiting the time the substrate spends within specific temperature zones during annealing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional annealing processes are used on semiconductor substrates with high oxygen chemical concentrations, then oxygen-related defects increase and doping concentration distribution becomes inconsistent, but extending annealing time or temperature to improve doping uniformity further increases thermal donor formation and characteristic variations
Solution Approach 1:
The patent applies parameter changes by precisely controlling annealing temperature and time parameters to suppress thermal donor formation. Specifically, the annealing is performed at 600°C or higher for 1 hour or less, or at 700°C or higher for 10 minutes or less, thereby achieving consistent doping concentration distribution while minimizing thermal donor-related breakdown voltage variations.
Solution Approach 2:
The patent applies preliminary action by performing annealing treatment before doping to pre-condition the semiconductor substrate. This preliminary annealing suppresses thermal donor formation in advance, ensuring that subsequent doping processes produce consistent doping concentration distributions without being compromised by later thermal donor formation.
2Manufacturing precision
If annealing time is extended to improve doping uniformity, then doping concentration distribution improves, but thermal donor concentration increases causing characteristic variations
Solution Approach 1:
The patent applies parameter changes by establishing specific annealing time-temperature relationships that achieve doping uniformity while limiting thermal donor formation. The method specifies annealing at 600°C or higher for 1 hour or less, or at 700°C or higher for 10 minutes or less, thereby optimizing both doping distribution and thermal donor suppression.
Solution Approach 2:
The patent applies skipping by rapidly passing through the temperature zone where thermal donors form (400-600°C) during annealing. By using higher annealing temperatures (600°C or higher) and shorter times, the process rushes through the critical thermal donor formation zone, achieving doping uniformity without allowing significant thermal donor accumulation.
3Reliability
If higher annealing temperatures are used to reduce thermal donor formation, then thermal donor concentration decreases, but doping uniformity may be compromised without sufficient time
Solution Approach 1:
The patent applies parameter changes by establishing complementary annealing conditions: either high temperature with short time (700°C or higher for 10 minutes or less) or moderate temperature with longer time (600°C or higher for 1 hour or less). These parameter combinations ensure both thermal donor suppression and adequate doping uniformity achievement.
Solution Approach 2:
The patent applies dynamics by providing flexible annealing parameter ranges that can be dynamically selected based on production requirements. The method allows choosing between different temperature-time combinations (600°C/1hr or 700°C/10min), enabling dynamic optimization between thermal donor suppression and doping uniformity according to specific device requirements.
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
By reducing the ratio of thermal donors to increased donors in the buffer region, the method effectively suppresses variations in semiconductor device characteristics, such as breakdown voltage, even when using semiconductor substrates with high oxygen chemical concentrations, thus improving manufacturing consistency and reducing costs.
Implementation Method 1
variations in oxygen chemical concentration and thermal donor formation, which affect the breakdown voltage
Implementation Method 2
controlling the thermal history of the semiconductor substrate during annealing to suppress the formation of thermal donors
Data Source
AI summary
Provided is a semiconductor device having a semiconductor substrate with the oxygen chemical concentration of 1×1016 atoms/cm3 or more, wherein it includes the bulk donor and an increased donor, includes a buffer region of a first conductivity type that has a doping concentration higher than that of the drift region, and has a concentration of the thermal donor that is 10% or less of a concentration of the increased donor at a same depth position throughout an entire first range from a lower end of the buffer region to the deepest peak.