Nitride Semiconductor p-Type Region With Controlled Mg Segregation
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Solution Overview
Problem
Nitride semiconductor devices face challenges in achieving high effective acceptor concentrations with good electrical characteristics due to high-density segregation or deep diffusion of Mg during high-temperature annealing, leading to decreased Mg concentration.
Innovation Solution
A nitride semiconductor device with a p-type region that includes a segregation part with controlled acceptor element concentration and a matrix with minimal segregation, achieved through precise ion implantation and annealing processes, ensuring a concentration range of 5×10^18 cm^-3 to 1×10^21 cm^-3 and a segregation ratio of 4.6 times or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Mg is heavily doped and subjected to annealing at high temperature, then the electrical characteristics are improved, but high-density segregation or deep diffusion of Mg occurs leading to decreased Mg concentration
Solution Approach 1:
The patent applies parameter changes by precisely controlling the annealing temperature (e.g., 1000-1200°C) and time to optimize the balance between electrical characteristic improvement and Mg concentration maintenance. This resolves the contradiction by finding optimal processing parameters that achieve good electrical characteristics while minimizing Mg segregation and diffusion.
Solution Approach 2:
The patent introduces an intermediary approach by using a two-step process: first implanting Mg to achieve desired concentration, then performing controlled annealing to activate the dopant while limiting segregation. This intermediary annealing step mediates between the need for electrical activation and the risk of concentration loss.
2Reliability
If annealing is performed at high temperature to activate acceptor element, then electrical characteristics are improved, but segregation of acceptor element increases
Solution Approach 1:
The patent changes the annealing parameters (temperature, time, atmosphere) to achieve a window where electrical characteristics are activated but segregation is controlled. By optimizing these parameters, the patent resolves the contradiction between achieving good electrical characteristics and maintaining compositional uniformity.
Solution Approach 2:
The patent applies partial action by performing annealing at moderate temperatures for controlled durations, achieving sufficient dopant activation without excessive segregation. This partial annealing approach avoids the extreme conditions that would cause severe compositional instability.
3Reliability
If ion implantation is used to achieve high acceptor concentration, then electrical characteristics are improved, but precise control of concentration distribution becomes difficult
Solution Approach 1:
The patent employs feedback control by measuring the actual dopant concentration and distribution after implantation and annealing, then adjusting subsequent processing steps to achieve the target concentration profile. This feedback mechanism resolves the contradiction by enabling precise control despite the inherent variability of ion implantation.
Solution Approach 2:
The patent replaces direct mechanical control of implantation parameters with a combination of implantation followed by thermal processing. By using annealing to redistribute and activate the dopant, the patent achieves better control over the final concentration distribution than implantation alone can provide.
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 solution results in a p-type region with higher effective acceptor concentration, lower sheet and contact resistance, and improved electrical characteristics, enhancing the operational stability and reliability of the nitride semiconductor devices.
Implementation Method 1
The p-type region includes a segregation part in which the acceptor element is partly segregated
Implementation Method 2
implanting impurity ions of an acceptor element from a front surface side of a nitride semiconductor into a predetermined region of the nitride semiconductor
Implementation Method 3
forming a p-type region in the predetermined region of the nitride semiconductor by subjecting, to annealing, the nitride semiconductor to which the acceptor element and the nitride are implanted
Implementation Method 4
implanting impurity ions of nitride from the front surface side into the predetermined region before or after the implanting the acceptor element
Data Source
AI summary
Provided is a nitride semiconductor device including a p-type region having a high effective acceptor concentration while exhibiting good electrical characteristics, and a method of manufacturing the same. The nitride semiconductor device includes: a nitride semiconductor; and a p-type region provided in the nitride semiconductor. The p-type region includes an acceptor element and entirely has a concentration in a range of 5×1018 cm−3 or higher and 1×1021 cm−3 or lower. The p-type region includes a segregation part in which the acceptor element is partly segregated, and a matrix in which the acceptor element is not segregated. The concentration of the acceptor element in the segregation part is 4.6 times or smaller as high as that in the matrix.