Junction termination structures for wide-bandgap power devices
View Patent ↗Disclosed are a variety of junction termination structures for high voltage semiconductor power devices. The structures are specifically aimed at providing a high breakdown voltage while being constructed with a minimal number of process steps. The combination of an RIE etch and/or implantation and anneal process with a finely patterned mesh provides the desired radial gradient for maximum breakdown voltage. The structures provide control of both the conductivity and charge density within the region. These structures can beneficially be applied to all high voltage semiconductor device structures, but are of particular interest for wide bandgap devices as they tend to have very high breakdown fields and scaled dimensions of the depletion layer width.
1. A method of making a high voltage power semiconductor device with a junction termination structure, comprising:
forming a high voltage power semiconductor device on a region of a substrate, the device having a peripheral edge;
forming at least first and second conductive rings around the device, the first ring spaced from the peripheral edge and the second ring spaced from the first ring; and
forming a resistive interconnection between the peripheral edge of the device and at least the first ring, the resistive interconnection being formed so as to provide an electrical path which stabilizes the voltages at each of the conductive rings and to provide a doped region that can be partially or completely depleted so that the electric field lines can be terminated on the charge in the depleted doped region;
the foregoing forming steps including:
depositing a doped semiconductive layer of a first thickness on the substrate;
forming the device in or on the doped semiconductor layer within the region of the substrate; and
etching a pattern in the doped semiconductor layer to define the peripheral edge of the device, and at least first and second rings spaced therefrom;
wherein the etching step etches entirely through the doped semiconductor layer in at least one gap between the device, the first ring and the second ring.
2. A method of making a high voltage power semiconductor device with a junction termination structure, comprising:
forming a high voltage power semiconductor device on a region of a substrate, the device having a peripheral edge;
forming at least first and second conductive rings around the device, the first ring spaced from the peripheral edge and the second ring spaced from the first ring; and
forming a resistive interconnection between the peripheral edge of the device and at least the first ring, the resistive interconnection being formed so as to provide an electrical path which stabilizes the voltages at each of the conductive rings and to provide a doped region that can be partially or completely depleted so that the electric field lines can be terminated on the charge in the depleted doped region;
the foregoing forming steps including:
depositing a doped semiconductive layer of a first thickness on the substrate;
forming the device in or on the doped semiconductor layer within the region of the substrate; and
etching a pattern in the doped semiconductor layer to define the peripheral edge of the device, and at least first and second rings spaced therefrom;
wherein the etching step etches partially through the doped semiconductor layer in at least one gap between the device, the first ring and the second ring.