From Silicon RF Power MOSFETS


The charge-coupled power MOSFET structures discussed in the previous chapter allow drastic reduction of the on-resistance of the drift region by utilizing the two-dimensional charge coupling between a source-connected electrode located within deep trenches and the donors in the drift region. By using a linearly graded doping profile, a rectangular shaped electric field profile can be generated in the drift region with doping levels ranging above 1 10 16 cm ?3. In addition, it was shown in the previous chapter that the charge coupling phenomenon distributes the electric field primarily in the N-type drift region with very little voltage developed across the P-base region. This allows reduction of the channel length which is beneficial for high frequency operation.

In the CC-MOSFET and GD-MOSFET structures described in the previous chapter, the channel is formed on the sidewall of the same trench within which the source-connected electrode is located. This imposes fabrication challenges because of the need to isolate the gate and source electrodes within the trench. In addition, the source-connected electrode in the trench must be periodically brought to the surface to make its electrical connection which disrupts the gate layout in the third dimension.

In this chapter, an alternate structure that utilizes the charge coupling concept is described with the gate region formed on the top surface [1]. This structure, named the super-linear (SL) MOSFET structure, can utilize either a uniform or a graded doping profile. In the previous chapter, it was shown that the...

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Metal-Oxide Semiconductor FET (MOSFET)
Metal-oxide semiconductor field-effect transistors (MOSFETs) are electronic switching devices with a conducting channel as the output. An electrode called a gate controls the width of the channel and determines how well the MOSFET conducts.
Power MOSFETs are majority carrier devices which have high input impedance and do not exhibit minority carrier storage effects, thermal runaway, or secondary breakdown. Power MOSFETs have higher breakdown voltages than bipolar junction transistors (BJTs) and can be used in higher frequency applications where switching power losses are important.
Junction Field-Effect Transistors (JFET)
Junction field-effect transistors (JFET) consist of a semiconductor channel in which the width and the conductivity of the channel is controlled by the space-charge region associated with the p-n region.
Insulated Gate Bipolar Transistors (IGBT)
Insulated gate bipolar transistors (IGBT) are bipolar transistors with an insulated gate. They combine the advantages of the bipolar transistor (high voltage and current) with the advantages of the MOSFET (low power consumption and high switching).
Oxidation Reduction Potential (ORP) Electrodes
Oxygen reduction potential (ORP) electrodes are analytical sensors for measuring oxidation-reduction potential (ORP).

Topics of Interest

Overview The super-linear (SL) MOSFET structure described in the previous chapter utilizes the charge-coupling concept to reduce the resistance in the drift region. The charge-coupling is achieved by...

Overview The super-linear (SL) MOSFET structure described in Chapter 7 utilizes the charge-coupling concept to reduce the resistance in the drift region. The charge-coupling is achieved by forming a...

3.1 Power MOSFET Structure and Operation In this section, the basic physics of operation of the power MOSFET will be described with the aid of the vertical DMOS structure. The same concepts are...

3.3 Power MOSFET On-Resistance As discussed in Chapter 2, the RF output power that can be delivered using a power MOSFET can be reduced by its on-resistance because it limits the lowest excursion of...

Overview The focus of this book is on silicon power MOSFETs used for cellular signal amplification. These devices contain a channel region, which enables control of the output current of the...