High-breakdown-voltage semiconductor apparatus

Abstract

A high-breakdown-voltage semiconductor apparatus is provided, wherein when a gate capacitance of that portion of a gate electrode, under which a channel is formed, is Cg[F], a resistance in a channel length direction of that portion of the gate electrode, under which the channel is formed, is Rg [Ω], a threshold voltage, which is to be applied to the gate electrode and application of which permits flow of a drain current, is Vth [V], a voltage to be applied to the gate electrode to cut off the drain current is Voff [V], and a ratio of increase in the drain voltage per unit time at the time of cutting off the drain current is dV/dt [V/s], the following condition is satisfied: |Vth−Voff|≧0.5·Cg·Rg·(dV/dt)

1. A high-breakdown-voltage semiconductor apparatus comprising:
 a first-conductivity-type base layer;    a second-conductivity-type base layer formed on a surface of the first-conductivity-type base layer;    a first-conductivity-type source layer formed on a surface of the second-conductivity-type base layer;    a gate electrode provided over that portion of the second-conductivity-type base layer, which is interposed between the first-conductivity-type source layer and the first-conductivity-type base layer, with a gate insulation film interposed between the gate electrode and the interposed portion of the second-conductivity-type base layer;    a second-conductivity-type drain layer formed on a surface of the first-conductivity-type base layer, which is opposed to the surface thereof on which the second-conductivity-type base layer;    a drain electrode put in contact with the second-conductivity-type drain layer; and    a source electrode put in contact with the first-conductivity-type source layer and the second-conductivity-type base layer,    wherein when a gate capacitance of that portion of the gate electrode, under which a channel is formed, is Cg [F],    a resistance in a channel length direction of that portion of the gate electrode, under which the channel is formed, is Rg [Ω],    a threshold voltage, which is to be applied to the gate electrode and application of which permits flow of a drain current, is Vth [V],    a voltage to be applied to the gate electrode to cut off the drain current is Voff [V], and    a ratio of increase in the drain voltage per unit time at the time of cutting off the drain current is dV/dt [V/s],    the following condition is satisfied: 
   |Vth−Voff|≧0.5·Cg·Rg·(dV/dt) 
   
     
     
       2. The high-breakdown-voltage semiconductor apparatus according to  claim 1 , wherein a width of that portion of the gate electrode, at which the gate electrode is connected to gate electrode wiring, is greater than a width of the gate electrode. 
     
     
       3. The high-breakdown-voltage semiconductor apparatus according to  claim 1 , further comprising a second gate electrode formed on the gate electrode. 
     
     
       4. The high-breakdown-voltage semiconductor apparatus according to  claim 3 , wherein the gate electrode and the second gate electrode are covered with insulation films. 
     
     
       5. The high-breakdown-voltage semiconductor apparatus according to  claim 3 , wherein the source electrode is not provided on the second gate electrode. 
     
     
       6. The high-breakdown-voltage semiconductor apparatus according to  claim 1 , further comprising a first-conductivity-type emitter layer formed on the first-conductivity-type base layer and having an impurity dosage of 1×10 13  [cm −3 ] or less and a peak concentration of 1×10 15  [cm −3 ] or more and 1×10 16  [cm −3 ] or less. 
     
     
       7. The high-breakdown-voltage semiconductor apparatus according to  claim 1 , wherein a thickness of that portion of the gate insulation film, which is formed below a central portion of the gate electrode, is different from a thickness of that portion of the gate insulation film formed below an end portion of the gate electrode. 
     
     
       8. The high-breakdown-voltage semiconductor apparatus according to  claim 1 , further comprising a resistor connected between the gate electrode and a gate power supply. 
     
     
       9. The high-breakdown-voltage semiconductor apparatus according to  claim 1 , wherein when a width of the gate electrode is L G , a depth of the first-conductivity-type base layer is D B , a thickness of the second-conductivity-type base layer is W B , and a distance between the gate electrodes is L S , the following condition is satisfied:
   60 μm≦L G , 5≦L G /L S , and 1≦L G   2 /(D B ·W B )≦9    
     
     
       10. A high-breakdown-voltage semiconductor apparatus comprising:
 a first-conductivity-type base layer;    a second-conductivity-type base layer formed on a surface of the first-conductivity-type base layer;    a first-conductivity-type source layer formed on a surface of the second-conductivity-type base layer;    a gate electrode provided over that portion of the second-conductivity-type base layer, which is interposed between the first-conductivity-type source layer and the first-conductivity-type base layer, with a gate insulation film interposed between the gate electrode and the interposed portion of the second-conductivity-type base layer;    a second-conductivity-type drain layer formed on a surface of the first-conductivity-type base layer, which is opposed to the surface thereof on which the second-conductivity-type base layer;    a drain electrode put in contact with the second-conductivity-type drain layer; and    a source electrode put in contact with the first-conductivity-type source layer and the second-conductivity-type base layer,    wherein when a gate capacitance of that portion of the gate electrode, under which a channel is formed, is Cg [F],    a resistance in a channel length direction of that portion of the gate electrode, under which the channel is formed, is Rg [Ω],    a threshold voltage, which is to be applied to the gate electrode and application of which permits flow of a drain current, is Vth [V],    a voltage to be applied to the gate electrode to cut off the drain current is Voff [V], and    a ratio of increase in the drain voltage per unit time at the time of cutting off the drain current is dV/dt [V/s],    the following condition is satisfied: 
   |Vth−Voff|≧0.5·Cg·Rg·(dV/dt)  
 and wherein the first-conductivity-type base layer is subjected to a local lifetime control process.  
   
     
     
       11. A method of a driving high high-breakdown-voltage semiconductor apparatuses, wherein each of the high high-breakdown-voltage semiconductor apparatuses comprises:
 a first-conductivity-type base layer;    a second-conductivity-type base layer formed on a surface of the first-conductivity-type base layer;    a first-conductivity-type source layer formed on a surface of the second-conductivity-type base layer;    a gate electrode provided over that portion of the second-conductivity-type base layer, which is interposed between the first-conductivity-type source layer and the first-conductivity-type base layer, with a gate insulation film interposed between the gate electrode and the interposed portion of the second-conductivity-type base layer;    a second-conductivity-type drain layer formed on a surface of the first-conductivity-type base layer, which is opposed to the surface thereof on which the second-conductivity-type base layer;    a drain electrode formed on the second-conductivity-type drain layer; and    a source electrode put in contact with the first-conductivity-type source layer and the second-conductivity-type base layer,    wherein when a gate capacitance of that portion of the gate electrode, under which a channel is formed, is Cg [F],    a resistance in a channel length direction of that portion of the gate electrode, under which the channel is formed, is Rg [Ω],    a threshold voltage, which is to be applied to the gate electrode and application of which permits flow of a drain current, is Vth [V],    a voltage to be applied to the gate electrode to cut off the drain current is Voff [V], and    a ratio of increase in the drain voltage per unit time at the time of cutting off the drain current is dV/dt [V/s],    the following condition is satisfied: 
   |Vth−Voff|≧0.5·Cg·Rg·(dV/dt)  
 and wherein the method of driving the high-breakdown-voltage semiconductor apparatuses comprises the steps of:  
   applying a first voltage to at least one of gates of the high-breakdown-voltage semiconductor apparatus, which is lower than a gate voltage at turn-on time, and    applying a second voltage for turning off to the at least one of the gates, which is lower than the first voltage.    
     
     
       12. The method of driving the high-breakdown-voltage semiconductor apparatus according to  claim 11 , further comprising the steps of:
 applying a third voltage to the at least one of the gates, which is lower than the first voltage, after the application of the first voltage.    
     
     
       13. A high- breakdown - voltage semiconductor apparatus comprising:      a first - conductivity - type base layer;        a second - conductivity - type base layer formed on a surface of the first - conductivity - type base layer;        a first - conductivity - type source layer formed on a surface of the second - conductivity - type base layer;        a gate electrode provided over that portion of the second - conductivity - type base layer which is interposed between the first - conductivity - type source layer and the first - conductivity - type base layer, with a gate insulation film interposed between the gate electrode and the interposed portion of the second - conductivity - type base layer;        a drain layer formed on a surface of the first - conductivity - type base layer, which is opposed to the surface thereof on which the second - conductivity - type base layer;        a drain electrode put in contact with the drain layer; and        a source electrode put in contact with the first - conductivity - type source layer and the second - conductivity - type base layer,        wherein when a gate capacitance of that portion of the gate electrode, under which a channel is formed, is Cg  ( F ) ,        a resistance in a channel length direction of that portion of the gate electrode, under which the channel is formed, is Rg  (Ω) ,        a threshold voltage, which is to be applied to the gate electrode and application of which permits flow of a drain current, is Vth  ( V ) ,        a voltage to be applied to the gate electrode to cut off the drain current is Voff  ( V ) , and        a ratio of increase in the drain voltage per unit time at the time of cutting off the drain current is dV/dt  ( V/s ) ,        the following condition is satisfied:      | Vth−Voff|≧ 0 . 5 ·Cg·Rg· ( dV/dt ).     
     
     
       14. The high- breakdown - voltage semiconductor apparatus according to    claim 13   ,      wherein the first - conductivity - type base layer is subjected to a local lifetime control process.