Semiconductor device and method for manufacturing semiconductor device
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Solution Overview
Problem
Semiconductor devices with integrated overvoltage protection elements face issues of short circuits during bonding due to molten metal and leak currents when mounted on substrates, as the entire semiconductor substrate acts as a P-layer, causing electron avalanche breakdown and current transmission to adjacent devices.
Innovation Solution
A semiconductor device design featuring a composite substrate with thermally-oxidized films and strategically positioned well regions of different conductivity types, along with external electrodes, to prevent short circuits and leak currents, including a diode structure unit that acts as a zener diode to protect against overvoltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the upper plane side wiring layer is joined to the light-emitting element with a molten metal bonding layer at heating treatment, then the bonding strength is improved, but the melted bonding layer contacts the semiconductor element causing a short circuit
Solution Approach 1:
The semiconductor substrate is segmented into multiple conductivity type regions (P-type region, N-type region, and intrinsic region) to create electrical isolation. This segmentation prevents the molten metal bonding layer from causing short circuits by ensuring that the light-emitting element and overvoltage protection element are electrically isolated through the intrinsic region, while still allowing strong mechanical bonding through the molten metal layer.
Solution Approach 2:
An intrinsic semiconductor region is introduced as an intermediary between the P-type and N-type regions. This intrinsic region acts as a electrical barrier that prevents current leakage and short circuits while allowing the bonding process to proceed. The intrinsic region mediates between the conflicting requirements of strong bonding and electrical isolation.
2Device complexity
If the whole region of the semiconductor substrate functions as a P layer, then the zener diode structure is simplified, but a leak current is transmitted to adjacent semiconductor devices causing operational failure
Solution Approach 1:
The semiconductor substrate is divided into distinct conductivity type regions: a P-type region for the zener diode, an N-type region for electrical isolation, and an intrinsic region for additional isolation. This segmentation prevents leak currents from spreading to adjacent devices while maintaining a relatively simple overall structure that can be manufactured using standard semiconductor processing techniques.
Solution Approach 2:
Different regions of the semiconductor substrate are assigned different conductivity types (P-type, N-type, intrinsic) to provide localized electrical properties. The P-type region provides the necessary characteristics for the zener diode operation, while the N-type and intrinsic regions provide localized electrical isolation to prevent leak current propagation to adjacent devices.
3Reliability
If the inter-electrode distance of mounting electrodes is increased to prevent short circuits, then the short circuit risk is reduced, but the mounting substrate area increases
Solution Approach 1:
An intrinsic semiconductor region is introduced as an intermediary between the P-type and N-type regions. This intrinsic region acts as a electrical barrier that prevents current leakage and short circuits while allowing the bonding process to proceed. The intrinsic region mediates between the conflicting requirements of strong bonding and electrical isolation.
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 effectively prevents short circuits and leak currents during bonding and overvoltage conditions, enhancing the reliability and performance of semiconductor devices by isolating the substrate and using a zener diode to manage voltage breakdown.
Implementation Method 1
The substrate has an upper surface and a lower surface on which thermally-oxidized films are formed
Implementation Method 2
a current caused by an electron avalanche breakdown of the semiconductor element (zener diode)
Data Source
AI summary
A light emitting device of the present invention includes a substrate, a semiconductor element, a first external electrode, and a second external electrode. The substrate has a first conductivity type and contains a single-crystal silicon. The substrate has an upper surface and a lower surface on which thermally-oxidized films are formed. A first opening portion and a second opening portion are formed to be mutually spaced in the thermally-oxidized film formed on the lower surface. The substrate includes a diode structure unit that includes a first well region and a second well region. The first well region is formed in a first region along the lower surface, is exposed at the first opening portion, and has a second conductivity type different from the first conductivity type. The second well region is formed in a second region along the lower surface in the first region, is exposed at the second opening portion, and has the first conductivity type. The semiconductor element is disposed on the substrate and includes a semiconductor layer. The first external electrode is formed on a lower surface of the thermally-oxidized film and in contact with the first well region at the first opening portion. The second external electrode is formed on the lower surface of the thermally-oxidized film, spaced from the first external electrode, and in contact with the second well region at the second opening portion. The second well region extends to the first opening portion side exceeding a middle line between the first opening portion and the second opening portion along the lower surface of the substrate.