Semiconductor device and crack detection method
Provided is a semiconductor device that can detect the cracking progress with high precision. A semiconductor device is formed using a semiconductor substrate, and includes an active region in which a semiconductor element is formed, and an edge termination region outside the active region. A crack detection structure is termed in the edge termination region of the semiconductor substrate. The crack detection structure includes: a trench formed in the semiconductor substrate and extending in a circumferential direction of the edge termination region; an inner-wall insulating film formed on an inner wall of the trench; an embedded electrode formed on the inner-wall insulating film and embedded into the trench; and a monitor electrode formed on the semiconductor substrate and connected to the embedded electrode.
1. A semiconductor device, comprising:
a semiconductor layer including an active region in which a semiconductor element is formed, and an edge termination region outside the active region; and
a crack detection structure formed in the edge termination region,
wherein the crack detection structure includes:
a trench formed in the semiconductor layer and extending in a circumferential direction of the edge termination region;
an inner-wall insulating film formed on an inner wall of the trench;
an embedded electrode formed on the inner-wall insulating film and embedded into the trench; and
a monitor electrode formed on the semiconductor layer and connected to the embedded electrode.
2. The semiconductor device according to claim 1 ,
wherein the semiconductor element is an insulated-gate semiconductor element including a gate insulating film and a gate electrode, and
the inner-wall insulating film of the crack detection structure is thicker than the gate insulating film of the semiconductor element.
3. The semiconductor device according to claim 1 ,
wherein the trench of the crack detection structure is formed in a drift layer of a first conductivity type in the semiconductor layer, and
a region of a second conductivity type at least surrounding a bottom of the trench in the drift layer is formed around the trench.
4. The semiconductor device according to claim 1 ,
wherein the semiconductor element is a trench-gate semiconductor element including a gate insulating film and a gate electrode that are embedded in a trench formed in the semiconductor layer, and
the trench of the crack detection structure is deeper than the trench of the semiconductor element.
5. The semiconductor device according to claim 1 ,
wherein the semiconductor element is a trench-gate semiconductor element including a gate insulating film and a gate electrode that are embedded in a trench formed in the semiconductor layer, and
the trench of the crack detection structure is wider than the trench of the semiconductor element.
6. A method for detecting a crack in the semiconductor device according to claim 1 , the method comprising:
measuring a leakage current or a potential difference between the monitor electrode of the crack detection structure and another electrode included in the semiconductor device; and
determining the presence or absence of a crack in the semiconductor device, based on a value of the leakage current or the potential difference that has been measured.