Power device and method for making the same

A method for manufacturing a power device, comprising:

• providing a power structure that includes:
• a substrate,
• a drift layer disposed on the substrate,
• an active region disposed in the drift layer,
• a terminal region disposed in the drift layer and surrounds the active region,
• a dielectric layer disposed on the drift layer and extending from a periphery of the active region to cover the terminal region,
• an electrode layer disposed on the active region, and
• a Schottky contact layer disposed between the active region and the electrode layer;
• forming an isolation layer on the electrode layer;
• and
• forming a passivation layer that covers at least a portion of the isolation layer and extends in a direction toward the terminal region, the passivation layer and the electrode layer being separated by the isolation layer,
• wherein
• the electrode layer has a mesa portion that extends above the dielectric layer, the mesa portion having a side wall proximate to the dielectric layer and a top surface distal from the drift layer, and
• the side wall of the mesa portion is connected to the dielectric layer.

A method for manufacturing a power device, comprising:

• providing a first power structure that includes:
• a substrate,
• a drift layer disposed on the substrate,
• an active region and a terminal region disposed in the drift layer distal from the substrate;
• a dielectric layer disposed on the drift layer and extending from a periphery of the active region to cover the terminal region,
• an electrode layer disposed on the active region, the electrode layer having a mesa portion that extends above the dielectric layer, the mesa portion having a side wall proximate to the dielectric layer and a top surface distal from the drift layer, the side wall of the mesa portion being connected to the dielectric layer so that an included angle is formed between the mesa portion and the dielectric layer, and
• a Schottky contact layer disposed between the active region and the electrode layer;
• forming an isolation layer on the electrode layer and the dielectric layer, the isolation layer having a slope surface extending in a direction from the side wall of the mesa portion toward the dielectric layer and away from the side wall;
• forming a photoresist on the isolation layer and patterning the photoresist so as to form a through hole in the photoresist that exposes a part of the isolation layer disposed on a central region of the electrode layer;
• patterning the isolation layer to remove the part of the isolation layer exposed from the through hole;
• and
• forming a passivation layer that covers at least a portion of the isolation layer, the passivation layer and the electrode layer being at least partially separated by the isolation layer,
• wherein
• the isolation layer has a thermal expansion coefficient a, the electrode layer has a thermal expansion coefficient b, the passivation layer has a thermal expansion coefficient c, and a>b>c.