Question

Problem 2[20 pts] [Ex 5.9] If we decrease the substrate doping concentration, how will the following parameters be affected? Parameters Accumulation region capacitance Flatband Voltage Depletion Region Capacitance Threshold Voltage Inversion Region Capacitance Increase Decrease Unchanged In each case, justify your answer.

Answer 1

dopvnt Concentration Va(-ive) Since Substrate dopg i euced hente there wih be very ess Acaundation af halea Intiale depletion Region , Thu Accunlasion Region Capacton Flat Bond Vo wilt kbe Very Cess holen wold Preset chaunel Region , hemce Very Low lo Bn ge will be Required hence It idecreaed J Depletion Egion Capacitance there in es No o hales Present.S At oepletion Condition ,P-n Tuncha Chan d亼Substiate is oned. due to Less No holes , there exinta Les N。 -we Jons and due to leso No. of Choges , Depletion region Capactamte in

decmeared, there wil be lass No. of heles io Subptradte Yegion to Tebel by oxide boerne Ch (Indhice ) hence At very Low Applied tire bat gate Coplete Inversion wilbe Achieved.hence tagreshel ET) Tvetsion region Cata Cionade Since there exint les thene for the formation a Inveraibs byer e exipt Less Tn Chonnel region At unchin formed buee