{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

115A_1_EE115A_W10-Chap6

115A_1_EE115A_W10-Chap6 - Chapter 6 Physics of MOS...

Info icon This preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 6 Physics of MOS Transistors head2right 6.1 Structure of MOSFET head2right 6.2 Operation of MOSFET 273 head2right 6.3 MOS Device Models head2right 6.4 PMOS Transistor head2right 6.5 CMOS Technology head2right 6.6 Comparison of Bipolar and CMOS Devices
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chapter Outline CH 6 Physics of MOS Transistors 274
Image of page 2
Metal-Oxide-Semiconductor (MOS) Capacitor CH 6 Physics of MOS Transistors 275 head2right The MOS structure can be thought of as a parallel-plate capacitor, with the top plate being the positive plate, oxide being the dielectric, and Si substrate being the negative plate. (We are assuming P-substrate.)
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Structure and Symbol of MOSFET CH 6 Physics of MOS Transistors 276 head2right This device is symmetric, so either of the n+ regions can be source or drain.
Image of page 4
State of the Art MOSFET Structure CH 6 Physics of MOS Transistors 277 head2right The gate is formed by polysilicon, and the insulator by Silicon dioxide.
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Formation of Channel CH 6 Physics of MOS Transistors 278 head2right First, the holes are repelled by the positive gate voltage, leaving behind negative ions and forming a depletion region. Next, electrons are attracted to the interface, creating a channel (“inversion layer”).
Image of page 6
Voltage-Dependent Resistor CH 6 Physics of MOS Transistors 279 head2right The inversion channel of a MOSFET can be seen as a resistor. head2right Since the charge density inside the channel depends on the gate voltage, this resistance is also voltage-dependent.
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Voltage-Controlled Attenuator CH 6 Physics of MOS Transistors 280 head2right As the gate voltage decreases, the output drops because the channel resistance increases. head2right This type of gain control finds application in cell phones to avoid saturation near base stations.
Image of page 8
MOSFET Characteristics CH 6 Physics of MOS Transistors 281 head2right The MOS characteristics are measured by varying V G while keeping V D constant, and varying V D while keeping V G constant. head2right (d) shows the voltage dependence of channel resistance.
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
L and t ox Dependence CH 6 Physics of MOS Transistors 282 head2right Small gate length and oxide thickness yield low channel resistance, which will increase the drain current.
Image of page 10
Effect of W CH 6 Physics of MOS Transistors 283 head2right As the gate width increases, the current increases due to a decrease in resistance.
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern