Semiconductor Device Gate Insulation Film Charging Prevention
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Solution Overview
Problem
Conventional semiconductor device manufacturing methods face issues where electron beam irradiation can charge the gate insulation film, leading to a low threshold voltage and increased parasitic built-in diode recovery loss.
Innovation Solution
A method involving a MOS structure forming step, electron beam irradiating step with the metal layer set to ground potential, metal layer dividing step, and annealing step to control lattice defects and prevent charging of the gate insulation film, ensuring a threshold voltage characteristic similar to devices without electron beam irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electron beam irradiation is performed to form lattice defects in the semiconductor base substrate, then parasitic built-in diode recovery loss is reduced, but the gate insulation film becomes charged causing threshold voltage to decrease
Solution Approach 1:
A metal layer is introduced as an intermediary component between the electron beam irradiation source and the gate insulation film. This metal layer acts as a charge sink that captures electrons during beam irradiation, preventing charge accumulation in the gate insulation film while allowing the electron beam to create the necessary lattice defects in the semiconductor substrate for reducing parasitic diode recovery loss
Solution Approach 2:
The metal layer is formed on the gate insulation film before electron beam irradiation occurs. This preliminary action prepares a charge acceptance structure in advance, so when electron beam irradiation is performed to create lattice defects, the excess charges are immediately captured by the pre-positioned metal layer rather than accumulating in the gate insulation film
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 method effectively controls parasitic built-in diode recovery loss and maintains a high threshold voltage characteristic by preventing gate insulation film charging, thus reducing electric current concentration and heat generation.
Implementation Method 1
an electron beam irradiating step where lattice defects are formed in the inside of the semiconductor base substrate by irradiating an electron beam to the semiconductor base substrate
Implementation Method 2
in a state where the metal layer is set to a ground potential... the gate insulation film is not charged
Implementation Method 3
an annealing step where the lattice defects in the semiconductor base substrate are repaired by heating the semiconductor base substrate
Data Source
AI summary
A method of manufacturing a semiconductor device includes in a following order: a first forming step where a gate electrode is formed on a first main surface side of a semiconductor base substrate with a gate insulation film interposed therebetween and, thereafter, an interlayer insulation film is formed to cover the gate electrode; a second forming step where a metal layer in a state of being connected with the gate electrode is formed over the interlayer insulation film; an irradiating step where a lattice defect is formed inside the semiconductor base substrate by irradiating an electron beam to the semiconductor base substrate in a state where the metal layer is set to a ground potential; a dividing step where the metal layer is divided into a plurality of electrodes; and an annealing step where the lattice defect in the semiconductor base substrate is repaired by heating the semiconductor base substrate.