Low voltage diode with reduced parasitic resistance and method for fabricating
AssigneeCree, Inc.
InventorsPrimit Parikh, Sten Heikman
Life of this patent
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Abstract
A method of making a diode begins by depositing an AlxGa1-xN nucleation layer on a SiC substrate, then depositing an n+ GaN buffer layer, an n− GaN layer, an AlxGa1-xN barrier layer, and an SiO2 dielectric layer. A portion of the dielectric layer is removed and a Schottky metal deposited in the void. The dielectric layer is affixed to the support layer with a metal bonding layer using an Au—Sn utectic wafer bonding process, the substrate is removed using reactive ion etching to expose the n+ layer, selected portions of the n+, n−, and barrier layers are removed to form a mesa diode structure on the dielectric layer over the Schottky metal, and an ohmic contact is deposited on the n+ layer.
Claims39
A method of making a diode, comprising:
- providing a substrate;
- depositing a plurality of semiconductor layers on said substrate;
- depositing a dielectric layer on the semiconductor layers;
- removing a portion of the dielectric layer;
- depositing a Schottky metal on the barrier layer in the void left by the removed portion of the dielectric layer;
- providing a conductive support layer;
- affixing the dielectric layer to the support layer with a metal bonding layer;
- removing the substrate to expose the one of the semiconductor layers adjacent said substrate;
- and
- depositing an ohmic contact on the exposed semiconductor layer.
A method of making a diode, comprising:
- providing a substrate;
- depositing a plurality of semiconductor layers on said substrate;
- depositing a Schottky metal on said plurality of semiconductor layers;
- selectively removing portions of the n+ and n− layers to form a mesa diode structure under the Schottky metal;
- removing the substrate under the mesa diode structure to form a via;
- and
- depositing an ohmic contact on the n+ layer in the via.
A method of making a diode, comprising:
- providing a GaN substrate;
- depositing a plurality of semiconductor layers on said substrate;
- depositing a Schottky metal on said semiconductor layers;
- thinning the substrate to reduce parasitic substrate resistance;
- and
- depositing an ohmic contact on the thinned substrate.
A diode, comprising:
- a conductive support layer;
- a Schottky metal layer;
- a semiconducting barrier layer disposed on the Schottky layer opposite the bonding layer;
- an n− semiconducting layer disposed on the barrier layer opposite the Schottky layer;
- an n+ semiconducting buffer layer disposed on the n− layer opposite the barrier layer;
- and
- an ohmic contact disposed on the n+ layer opposite the n− layer.
A diode, comprising:
- a conductive support layer;
- a Schottky metal layer;
- a metal bonding layer affixing the Schottky layer to the support layer;
- a 0-20 Å thick semiconducting barrier layer of AlxGa1-xN, with 0.15≦x≦0.45, disposed on the Schottky layer opposite the bonding layer;
- an n− semiconducting layer of GaN, between 0.5 and 5 μm thick and doped with an impurity concentration of between 1×1015/cm3 and 1×1017/cm3, disposed on the barrier layer opposite the Schottky layer;
- an n+ semiconducting buffer layer of GaN, between 0.5 and 5 μm thick and doped with an impurity concentration of between 5×1017/cm3 and 5×1019/cm3, disposed on the n− layer opposite the barrier layer;
- and
- an ohmic contact disposed on the n+ layer opposite the n− layer.
A diode, comprising:
- a GaN substrate, the thickness of which is reduced to reduce parasitic resistance;
- an n+ semiconducting buffer layer disposed on the substrate;
- an n− semiconducting layer disposed on the n+ layer;
- a semiconducting barrier layer disposed on the n− layer;
- a Schottky metal layer disposed on the barrier layer;
- and
- an ohmic contact disposed on the thinned substrate.
A diode, comprising:
- a GaN substrate, the thickness of which is reduced to reduce parasitic resistance;
- an n+ semiconducting buffer layer of GaN, between 0.5 and 5 μm thick and doped with an impurity concentration of between 5×1017/cm3 and 5×10′9/cm3, disposed on the substrate;
- an n− semiconducting layer of GaN, between 0.5 and 5 μm thick and doped with an impurity concentration of between 1×1015/cm3 and 1×1017/cm3, disposed on the n+ layer;
- a 0-20 Å thick semiconducting barrier layer of AlxGa1-xN, with 0.15≦x≦0.45, disposed on the n− layer;
- a Schottky metal layer disposed on the barrier layer;
- and
- an ohmic contact disposed on the thinned substrate.
Dependencies are inferred from the claim text.