DC/DC converter using bipolar transistor, method of manufacturing the same and DC power supply module using the same

Abstract

A DC/DC converter is comprised of a bipolar transistor, an inductor, a smoothing capacitor, an input terminal, an output terminal, and a grounded terminal. A base of the transistor includes a silicon germanium layer. The bipolar transistor has a high switching speed and a low on-state voltage through an optimization of a structure of the transistor.

1 - 33 . (canceled)  
   
   
       34 . A SiGe bipolar transistor comprising: 
 a silicon collector layer containing N-type dopants;    an silicon emitter layer containing N-type dopants; and    a silicon germanium base layer, containing P-type dopants and placed between the collector layer and the emitter layer,    wherein a germanium concentration of the base layer increases up to 6 to 16% as a distance from the collector layer decreases,    wherein a thickness of the base layer is 60 to 90 nm, and    wherein a dopant concentration of the collector layer is 5×10 14  to 1×10 16  cm −3 ,    whereby the SiGe bipolar transistor is operable to repeatedly turn on and off at high frequency to generate a DC power.    
   
   
       35 . The SiGe bipolar transistor according to  claim 34 , wherein a thickness of the collector layer is 1.5 to 2.5 μm.  
   
   
       36 . A SiGe bipolar transistor comprising: 
 a silicon collector layer containing N-type dopants;    an silicon emitter layer containing N-type dopants; and    a base layer containing P-type dopants and placed between the collector layer and the emitter layer,    wherein the base layer includes a silicon germanium layer having a germanium concentration of 6 to 16%,    wherein the base layer has a thickness of 60 to 90 nm, and    wherein a dopant concentration of the collector layer is 5×10 14  to 1×10 16 cm   −3 ,    whereby the SiGe bipolar transistor is operable to repeatedly turn on and off at high frequency to generate a DC power.    
   
   
       37 . The SiGe bipolar transistor according to  claim 36 , wherein a thickness of the collector layer is 1.5 to 2.5 μm.  
   
   
       38 . The SiGe bipolar transistor according to  claim 36 , wherein the base layer further includes an additional silicon germanium layer having a germanium concentration less than that of the silicon germanium layer, 
 wherein the silicon germanium layer is connected with the collector layer, and the additional silicon germanium layer is connected with the emitter layer.    
   
   
       39 . The SiGe bipolar transistor according to  claim 36 , wherein the base layer further includes a silicon layer, 
 wherein the silicon germanium layer is connected with the collector layer, and the silicon layer is connected with the emitter layer.    
   
   
       40 . A method of manufacturing a silicon germanium bipolar transistor comprising: 
 forming an N-type silicon collector layer, having a dopant concentration of 5×10 14  to 1×10 16  cm −3  on an N-type silicon substrate;    forming a P-type silicon germanium base layer of having a thickness of 60 to 90 nm on the N-type collector layer, wherein a germanium concentration of the P-type silicon germanium base layer increases up to 6 to 16% as a distance from the collector layer decreases; and    forming an N-type silicon emitter layer.    
   
   
       41 . A DC/DC converter comprising: 
 an input terminal receiving DC power input;    an output terminal;    a grounded terminal;    a smoothing capacitor connected between the output and grounded terminals; and    a bipolar transistor for switching the DC power input received from the input terminal to generate DC power output on the output terminal,    wherein a base layer of the bipolar transistor includes a silicon germanium layer.    
   
   
       42 . The DC/DC converter according to  claim 41 , wherein a germanium concentration of the silicon germanium layer increases up to 6 to 16% as a distance from a collector layer of the bipolar transistor decreases, wherein a thickness of the base layer is 60 to 90 nm, and wherein a dopant concentration of the collector layer is 5×10 14  to 1×10 16  cm −3 .  
   
   
       43 . The DC/DC converter according to  claim 41 , wherein the silicon germanium layer has a germanium concentration of 6 to 16%, 
 wherein the base layer has a thickness of 60 to 90 nm, and    wherein a dopant concentration of the collector layer is 5×10 14  to 1×10 16  cm −3 .    
   
   
       44 . The DC/DC converter according to  claim 41 , wherein a thickness of the collector layer is 1.5 to 2.5 μm.  
   
   
       45 . The DC/DC converter according to  claim 43 , wherein the base layer further includes an additional germanium layer having a germanium concentration less than that of the silicon germanium layer, 
 wherein the silicon germanium layer is connected with the collector layer, and the additional silicon germanium layer is connected with an emitter layer of the bipolar transistor.    
   
   
       46 . The DC/DC converter according to  claim 43 , wherein the base layer further includes a silicon layer, 
 wherein the first silicon germanium layer is connected with the collector layer, and the silicon layer is connected with the emitter layer.    
   
   
       47 . A DC/DC conversion method comprising: 
 receiving DC power input at an input terminal;    switching the DC power input received at the input terminal with a bipolar transistor to generate DC power output, wherein a base layer of the bipolar transistor includes a silicon germanium layer; and    outputting the DC power output.    
   
   
       48 . The DC/DC conversion method according to  claim 47 , wherein the DC power input is switched at a switching frequency of several tens of MHz.  
   
   
       49 . The DC/DC conversion method according to  claim 47 , wherein a germanium concentration of the silicon germanium layer increases up to 6 to 16% as a distance from a collector layer of the bipolar transistor decreases, 
 wherein a thickness of the base layer is 60 to 90 nm, and    wherein a dopant concentration of the collector layer is 5×10 14  to 1×10 16  cm −3 .    
   
   
       50 . The DC/DC conversion method according to  claim 47 , wherein the silicon germanium layer has a germanium concentration of 6 to 16%, 
 wherein the base layer has a thickness of 60 to 90 nm, and    wherein a dopant concentration of the collector layer is 5×10 14  to 1×10 16  cm −3 .    
   
   
       51 . The DC/DC conversion method according to  claim 50 , wherein the base layer further includes an additional germanium layer having a germanium concentration less than that of the silicon germanium layer, 
 wherein the silicon germanium layer is connected with the collector layer, and the additional silicon germanium layer is connected with an emitter layer of the bipolar transistor.    
   
   
       52 . The DC/DC conversion method according to  claim 50 , wherein the base layer further includes a silicon layer, 
 wherein the first silicon germanium layer is connected with the collector layer, and the silicon layer is connected with the emitter layer.    
   
   
       53 . A method of manufacturing a DC/DC converter comprising: 
 preparing a silicon germanium bipolar transistor; and    assembling the silicon germanium bipolar transistor, an inductor, a smoothing capacitor, a diode, an input terminal, an output terminal, and a grounded terminal into a DC/DC converter,    wherein a collector of the silicon germanium bipolar transistor is connected to the input terminal,    wherein the inductor is connected between the input terminal and an emitter of the bipolar transistor,    wherein the smoothing capacitor is connected between the output and grounded terminals, and    wherein the diode is connected between the emitter of the silicon germanium bipolar transistor and the grounded terminal.