| 摘要 |
PROBLEM TO BE SOLVED: To provide a MOS reference voltage circuit having a small temperature drift (voltage change due to a temperature) of a reference voltage, and to provide a method for manufacturing the same. SOLUTION: The method for manufacturing the MOS reference voltage circuit comprises a step of deciding an impurity dose (Dep Dose amount Xd[×10<12> cm<-2> ]) at the time of ion implanting when an n-type layer 6 of a channel of a depletion type n-channel MOSFET 21 is formed according to a formula of 0.9×[[Tm+(1.75Ld+230)]/(0.3Ld+149)]<=Xd<=1.1×[[Tm+(1.75Ld+230)]/(0.3Ld+149)]. Ld is a channel length (μm), and Tm is an intermediate temperature ( deg.C), and is (T1+T2)/2. Thus, in a temperature range of T1<=T<=T2, a change of an output voltage of the MOS reference voltage circuit can be suppressed to a predetermined small value (e.g. 10 mV in the case of T1=-10 deg.C, T2=70 deg.C) or less.
|
