1 / 14

MOSFET CHARACTERIZATION LAB

MOSFET CHARACTERIZATION LAB. How to Find K and Vto o. How to Find K and Vto o. ohmic contact effect. slope =. to be discussed in a future slide. V GS. Vto o. How to Find K and Vto o. Sub-threshold Conduction. ln(I D ). leakage. Vto. V GS. Sub-threshold Conduction.

autumn-levine
Download Presentation

MOSFET CHARACTERIZATION LAB

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MOSFET CHARACTERIZATION LAB

  2. How to Find K and Vtoo

  3. How to Find K and Vtoo ohmic contact effect slope = to be discussed in a future slide VGS Vtoo

  4. How to Find K and Vtoo

  5. Sub-threshold Conduction ln(ID) leakage Vto VGS

  6. Sub-threshold Conduction

  7. Channel Length Modulation

  8. Channel Length Modulation (2)

  9. Finding l triode: VDS < VGS - Vtoo saturation: VDS > VGS - Vtoo ID VGS3 > VGS2 VGS2 > VGS1 VGS1 > Vtoo VDS -1 / l

  10. Finding l

  11. Instructions for MOSFET Characterization Lab (1) a) Find k and Vto for the NMOS device of the CD 4007. Use the circuit below: Important: Current (I) should not exceed 5 ma ! Also connected to pin 14 putting all PMOS bodies at VDD U13 PIN5 + VGS = VDS PIN3 - Also connected to pin 7 putting all NMOS bodies at Vss U15 PIN4 I U17 U18 Note: with VGS = VDS, we require VGS – Vto < VDS so the device is in saturation. Take enough points to get a reasonable curve to find k and Vto, as well as observing the sub-threshold and ohmic regions.

  12. Instructions for MOSFET Characterization Lab (2) b) For the NMOS device of the CD4007, find the full-drain characteristics for VGS = 2, 3, 4, 5 Volts. Use the data to find l. U5 U3 U9 must be connected to U8 I Pin 5 U11 + U12 VDS Pin 3 - + Pin 4 Also connects to pin 7 putting all NMOS bodies at Vss VGS - U9 U10 U7 Important: Limit VDS to 10 Volts and I to 5 ma. The device goes into the non-saturation region when VGS – Vto > VDS. Do not use this data to calculate l.

  13. Instructions for MOSFET Characterization Lab (3) c) Repeat part (a) for the PMOS device of a CD 4007 and find k and Vtoof the device. Note Vto is negative. A PMOS device is in saturation when VDS < VGS – Vto where VGS and VDS are negative for a PMOS enhancement device. With VGS = VDS, VDS is always less than VGS – Vto . Conclusion: for the circuit below, the device is always saturated. U15 must be connected to U18 Pin 14 also puts all PMOS bodies at VDD U13 PIN14 + PIN6 Vpower supply =(-VGS) = (-VDS) - PIN13 U14 U17 I U16 Also connected to pin 7 Puts all NMOS bodies at ground Take enough points to get a reasonable curve to find k and Vto, as well as observing the sub-threshold and ohmic regions.

  14. Instructions for MOSFET Characterization Lab (4) d) Repeat part (b) for the PMOS device of a CD 4007. Use VGS = -2, -3, -4, and –5 Volts. Find l. l should be negative since ID = K (VGS – Vto)2(1 + lVDS) and VDS is negative. U7 + U9 U10 V power supply 2 = (-VGS) PIN14 Vpower supply 1 = (-VDS) + U1 - - PIN6 U4 PIN13 U5 I U3 Pin 14 also puts all PMOS bodies at VDD U2 must be connected to U9 Important: Limit VDS to –10 volts and I to 5 ma. The device goes into its non-saturation region when VGS – Vto < VDS. Do not use this data to calculate l.

More Related