Integrated vertical trench mos transistor

Abstract

A VTMOS transistor in semiconductor material of a first type of conductivity includes a body region of a second type of conductivity and a source region of the first type of conductivity. A gate region extends into the main surface through the body region and is insulated from the semiconductor material. A region of the gate region extends onto the main surface is insulated from the rest of the gate region. An anode region of the first type of conductivity is formed into said insulated region, and a cathode region of the second type of conductivity is formed into said insulated region in contact with the anode region; the anode region and the cathode region define a thermal diode electrically insulated from the chip.

1 . A method, comprising:
 forming an electronic device having a vertical trench MOS transistor in a semiconductor material of a first type of conductivity, the forming of the electronic device includes:
 forming a body region of a second type of conductivity extending into the semiconductor material from a main surface of the semiconductor material; 
 forming a source region of the first type of conductivity extending into the body region from the main surface; 
 forming a gate region of conductive material extending into the semiconductor material from the main surface through the body region, the gate region being insulated from the semiconductor material, the forming of the gate region including:
 forming a gate structure extending into the semiconductor material from the main surface through the body region and onto the main surface; 
 insulating a region of the gate structure extending on the main surface from a remainder of the gate structure; and 
 forming the gate region from the remainder of the gate structure; 
 
 forming an anode region of the first type of conductivity into said insulated region; and 
 forming a cathode region of the second type of conductivity into said insulated region in contact with the anode region, the anode region and the cathode region defining a thermal diode electrically insulated from the semiconductor material. 
   
     
     
         2 . The method according to  claim 1  wherein forming the gate structure comprises:
 forming a trench extending into the semiconductor material from the main surface through the body region; 
 forming an insulating layer onto the main surface and onto a boundary surface of the trench; 
 forming a first conductive layer onto the insulating layer; 
 forming a second conductive layer onto the first conductive layer to fill the trench; and 
 removing the second conductive layer outside the trench to expose the first conductive layer on the main surface. 
 
     
     
         3 . The method according to  claim 2  wherein the first conductive layer includes un-doped polysilicon, and the second conductive layer includes doped polysilicon. 
     
     
         4 . The method according to  claim 2  wherein the removing the second conductive layer outside the trench includes:
 performing a chemical-mechanical polishing. 
 
     
     
         5 . The method according to  claim 2  wherein the insulating a region of the gate structure includes:
 removing a portion of the first conductive layer. 
 
     
     
         6 . The method according to  claim 2  wherein the forming an anode region includes:
 performing a first ion implantation of dopants of the first type of conductivity into a first part of the first conductive layer defining said insulated region; 
 
       and wherein the forming a cathode region includes:
 performing a second ion implantation of dopants of the second type of conductivity into a second part of the first conductive layer defining said insulated region. 
 
     
     
         7 . The method according to  claim 6  wherein the forming a gate region includes:
 performing said first ion implantation of dopants of the first type of conductivity further into at least part of the remainder of the gate structure; 
 
       and wherein the forming a body region includes:
 performing said second ion implantation of dopants of the second type of conductivity further into the semiconductor material. 
 
     
     
         8 . An electronic device, comprising:
 a semiconductor substrate of a first type of conductivity;   a vertical trench MOS transistor integrated in the semiconductor substrate;   a body region of a second type of conductivity extending in the semiconductor substrate from a main surface of the semiconductor substrate;   a source region of the first type of conductivity extending in the body region from the main surface;   a gate region of conductive material extending in the semiconductor substrate from the main surface through the body region, the gate region being insulated from the semiconductor substrate;   a region insulated from the gate region and from the semiconductor substrate on the main surface;   a thermal diode electrically insulated from the semiconductor substrate, the thermal diode including:
 an anode region of the first type of conductivity in said insulated region; 
   
       and
   a cathode region of the second type of conductivity in said insulated region in contact with the anode region, the anode region and the cathode region.   
 
     
     
         9 . The device of  claim 8  wherein the gate structure includes:
 a trench extending into the semiconductor substrate from the main surface through the body region; 
 an insulating layer onto the main surface and onto a boundary surface of the trench; 
 a first conductive layer onto the insulating layer; and 
 a second conductive layer onto the first conductive layer to fill the trench. 
 
     
     
         10 . A system, comprising:
 an electronic device that includes:
 a semiconductor substrate of a first type of conductivity; 
 a vertical trench MOS transistor integrated on the semiconductor substrate; 
 a body region of a second type of conductivity extending in the semiconductor substrate from a main surface of the semiconductor substrate; 
 a source region of the first type of conductivity extending in the body region from the main surface; 
 a gate region of conductive material extending in the semiconductor substrate from the main surface through the body region, the gate region being insulated from the semiconductor substrate; 
 a region insulated from the gate region and from the semiconductor substrate on the main surface; 
 a thermal diode electrically insulated from the semiconductor substrate, the thermal diode including:
 an anode region of the first type of conductivity in said insulated region; and 
 a cathode region of the second type of conductivity in said insulated region in contact with the anode region, the anode region and the cathode region; and 
 
   a first module configured to bias the thermal diode;   a second module configured to measure an electrical quantity of the thermal diode; and   a third module configured to determine an operating temperature of each vertical trench MOS transistor in response to the measured electrical quantity.   
     
     
         11 . The system of  claim 10  wherein the gate structure includes:
 a trench extending into the semiconductor substrate from the main surface through the body region; 
 an insulating layer onto the main surface and onto a boundary surface of the trench; 
 a first conductive layer onto the insulating layer; and 
 a second conductive layer onto the first conductive layer to fill the trench. 
 
     
     
         12 . A device, comprising:
 a substrate having a first surface and a second surface;   a transistor formed in the substrate, the transistor including:
 a first terminal formed on the second surface of the substrate; 
 a second terminal formed on the first surface of the substrate; 
 a gate formed on and in the substrate; 
 an insulating layer configured to separate the gate from the substrate; 
   a thermal diode formed on the substrate and being thermally isolated from the substrate by the insulating layer, the thermal diode including:
 an anode spaced from the gate by a distance; and 
 a cathode separated from the gate by the anode. 
   
     
     
         13 . The device of  claim 12  wherein the substrate includes a layer of a first conductivity type adjacent to the first terminal and a body region of a second conductivity type. 
     
     
         14 . The device of  claim 12 , further comprising a trench, the gate being formed in the trench. 
     
     
         15 . The device of  claim 14  wherein the insulating layer is on the second surface of the substrate and on an interior surface of the trench. 
     
     
         16 . The device of  claim 15  wherein the gate includes a first portion in the trench and second portions that are above the first surface of the substrate and extend further than the interior surface of the trench.