16p channeldeviceTwo reasons for readers to befamiliar withp channel device Existence in discrete-circuit>Moreimportant is theutilization of complementaryMOS or CMOS circuits.2025/11/27
2025/11/27 16 ⚫ Two reasons for readers to be familiar with p channel device p channel device ➢ Existence in discrete-circuit. ➢ More important is the utilization of complementary MOS or CMOS circuits
17p channeldeviceStructure of p channel deviceThe substrate is n type and the inversionlayer is p type.Carrier is hole.Thresholdvoltageisnegative.All thevoltages and currents are opposite tothe ones of nchannel device.Physical operationis similarto that of n channel device2025/11/27
2025/11/27 17 ⚫ Structure of p channel device ➢ The substrate is n type and the inversion layer is p type. ➢ Carrier is hole. ➢ Threshold voltage is negative. ➢ All the voltages and currents are opposite to the ones of n channel device. ➢ Physical operation is similar to that of n channel device. p channel device
18Complementary MOS orCMOSNMOSPMOSSGDDGSQ.GateCCCePolysiliconoxideSioSioThickSiO,(isolation)1t12nwellp-typebody> ThePMOS transistorisformed inn well> Anotherarrangement is also possible in which an n-type body is used andthe n device is formed in a p well.> CMOs is the most widely used of all the analog and digital IC circuits2025/11/27
2025/11/27 18 ➢ The PMOS transistor is formed in n well. ➢ Another arrangement is also possible in which an n-type body is used and the n device is formed in a p well. ➢ CMOS is the most widely used of all the analog and digital IC circuits. Complementary MOS or CMOS
19Current-voltage characteristicsCircuit symbolOutput characteristic curvesChannellengthmodulationCharacteristicsofpchanneldeviceBodyeffectTemperature effects and Breakdown Region2025/11/27
2025/11/27 19 ⚫ Circuit symbol ⚫ Output characteristic curves ⚫ Channel length modulation ⚫ Characteristics of p channel device ⚫ Body effect ⚫ Temperature effects and Breakdown Region Current-voltage characteristics
20CircuitsymbolDDDQOOOBOBGOGOGO0OoSSs(a)(b)(c)(a)Circuit symbol for the n-channel enhancement-type MOSFET.(b)Modified circuit symbol withan arrowhead onthe sourceterminal todistinguish it from the drain and to indicate device polarity (i.e., n channel)(c)Simplified circuitsymbol to be used when the source is connected to thebody or when the effect of the body on device operation is unimportant.2025/11/27
2025/11/27 20 (a) Circuit symbol for the n-channel enhancement-type MOSFET. (b) Modified circuit symbol with an arrowhead on the source terminal to distinguish it from the drain and to indicate device polarity (i.e., n channel). (c) Simplified circuit symbol to be used when the source is connected to the body or when the effect of the body on device operation is unimportant. Circuit symbol