PMOS VS NMOS TRANSISTOR SIMULATOR

Diffusion Capacitor n+ (N D ) depletion region substrate (N A ) bottomwall capacitance sidewall capacitancesġ4 Transistor Resistance : Two Components: Drain/ Sources Resistance: R D(S) = Rsh x no. Length Lateral diffusion L D = 0.7Xj L eff = L drawn - 2L D L drawn L D L eff L D polysiliconġ3 Semiconductor Capacitors 1. Width Oxide encroachment W eff = W drawn - 2W D 2. ( l /w ) Rsh = sheet resistance Ω /  For 0.5u process: N+ diffusion : 70 Ω/  M1: 0.06 Ω/  P+ diffusion : 140 Ω/  M2: 0.06 Ω/  Polysilicon : 12 Ω/  M3: 0.03 Ω/  Polycide:2-3 Ω/  P-well: 2.5K Ω/  N-well: 1K Ω/  w current l t (A)ġ1 Semiconductor Resistors Al n+ Diffusion n+ Field oxide polysilicon Polysilicon Resistor Diffusion Resistor SiO2ġ2 Variations in Width and Length W eff W drawn WDWD W D 1. n Channel hot electrons: If the Vds is increased, then the lateral electric field is increased and the electric field accelerates the electrons near the drain with high kinetic energy they are injected into the oxide near the drain.ġ0 Semiconductor Resistors Resistance R=  ( l /A) = (  /t). Due to the acceleration of electrons by the Vds, electrons and holes gaining high speed can penetrate the gate insulator and change its characteristics. n Hot carrier: As a results of scaling, device dimensions are reduced while, doping concentrations are increased, while voltages are not reduced to the same proportion, as a consequence there is an increase in electric field in the channel region while, the thickness of the gate insulating layer is thinner. a) Draw the top view of a 4-terminal nMOS transistor showing all of the layout laycrs and features necessary to construct a complete four-terminal device. S SUPPLY VOLTAGEV DD 1/S V DD /S Linear Scalingħ Velocity Saturation and mobility Degradationĩ Secondary Effects n Subthreshold current: is the small current that flows from drain at Vgs < Vt n Punch through: If a large voltage is applied to Vds, then the depletion region of the drain can extend to the source, a punch through occurs and under these condition a large current can flow from the drain to source. Draw the cross-section (profile) of a 4-terminal nMOS transistor and label all important regions of the device. This article on NMOS Vs PMOS MOSFET describes the basic difference between NMOS and PMOS types of MOSFET.

PMOS VS NMOS TRANSISTOR SIMULATOR

The simulations have been carried out using libraries from TSMC foundry and the device has been simulated using Virtuoso Cadence Spectre Simulator version 6.1.5 with HSPICE.Presentation on theme: '1 Models for Hand Analysis NMOS Transistor PMOS Transistor V DSN  V GSN -V TN V DSN  V GSN -V TN V DSP  V GSP -V TP V DSP  V GSP -V TP K N =(W/L)K’'- Presentation transcript:ġ Models for Hand Analysis NMOS Transistor PMOS Transistor V DSN  V GSN -V TN V DSN  V GSN -V TN V DSP  V GSP -V TP V DSP  V GSP -V TP K N =(W/L)K’ N K P =(W/L)K’ PĢ pMOS Current model VDSP>VGSP -VTP VDSP designing using MOSFETs at deep sub micron levels, needs a careful study of the behaviour of short channel devices for the parameter variations such as threshold voltage, channel length leading to high leakage currents and poor performance of devices.

For DSM technology nodes leakage current dominates the devices. Silicon material processes technology has undergone a change in process material and technology beyond 180nm node. But this trend seem to end beyond deep sub micron levels due to main design constraints such as short channel effects (SCE), and variations in process design parameters leading to high leakage currents. The continuous scaling of semiconductor devices has kept pace with Moore’s law and transistors below 1µm are grouped under deep sub-micron (DSM) technology node. Semiconductor technology has reached an end in the manufacture of conventional Metal Oxide semiconductor Field Effect Transistor (MOSFET).

Pmos vs nmos transistor