Power device

Abstract

The invention provides a power device, which includes: an operation layer, including a top surface, a body region and a drift region, the body region and the drift region being connected in a lateral direction, to form a PN junction along a channel width direction between the body region and the drift region; a gate, formed on the top surface, and the PN junction is located under the gate; a source, formed in a portion of the operation layer between the body region and the top surface; a drain, formed in another portion of the operation layer between the drift region and the top surface; a first conduction portion, formed on the top surface for electrically connecting the source; a conduction layer, formed on the first conduction portion and electrically connected to the source via the first conduction portion; and a second conduction portion, formed on the top surface and between the conduction layer and the drift region in a thickness direction, for electrically connecting the drift region and the conduction layer, wherein a Schottky diode is formed by the second conduction portion and the drift region.

What is claimed is: 
     
         1 . A power device, comprising:
 an operation layer, including atop surface, a body region of a first conductive type and a drift region of a second conductive type, the body region and the drift region are connected in a lateral direction, to form a PN junction along a channel width direction between the body region and the drift region;   a gate, formed on the top surface, and the PN junction is located under the gate in a thickness direction;   a source of the second conductive type, the source being formed in a portion of the operation layer between the body region and the top surface;   a drain of the second conductive type, the drain being formed in a portion of the operation layer between the drift region and the top surface;   a first conduction portion, formed on the top surface for electrically connecting the source;   a conduction layer, formed on the first conduction portion and being electrically connected to the source via the first conduction portion; and   at least one second conduction portion, formed on the top surface and between the conduction layer and the drift region in a thickness direction, to electrically connect the drift region and the conduction layer, wherein a Schottky diode is formed by the second conduction portion and the drift region;   wherein the gate is located between the first conduction portion and the second conduction portion in the lateral direction.   
     
     
         2 . The power device of  claim 1 , wherein there are a plurality of second conduction portions arranged separately along the channel width direction, wherein when the power device is in a normal operation including a conduction state and a non-conduction state, a depletion region is continuously formed without break in the drift region, to encompass a junction between the drift region and the second conduction portion under the top surface. 
     
     
         3 . The power device of  claim 1 , wherein the gate includes at least one first opening above the drift region, to accommodate the second conduction portion in the first opening. 
     
     
         4 . The power device of  claim 1 , wherein the second conduction portion is a continuous structure without break along the channel width direction. 
     
     
         5 . The power device of  claim 1 , further comprising a field oxide structure, which is located between the drift region and the gate in the thickness direction. 
     
     
         6 . The power device of  claim 5 , wherein the field oxide structure includes at least one second opening above the drift region, to accommodate one of the second conduction portions in the second opening. 
     
     
         7 . The power device of  claim 5 , further comprising a first conductive type shallow doped region, which is located between the field oxide structure and the drift region, and in contact with the field oxide structure. 
     
     
         8 . The power device of  claim 5 , wherein a portion of the gate is formed on the top surface and another portion of the gate is formed on the field oxide structure. 
     
     
         9 . The power device of  claim 1 , wherein the power device is used in a synchronous switching regulator which is configured to operably generate an output voltage according to an input voltage, wherein the power device includes an upper bridge switch and a lower bridge switch, and the lower bridge switch includes the power device.