From Silicon RF Power MOSFETS


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 source connected electrode within a deep trench that surrounds the (mesa) drift region. In addition to allowing high doping concentrations in the drift region, the charge-coupling distributes the electric field below the P-base region resulting in a low electric field at the surface. This enables maintaining the channel in the linear mode of operation even at high drain bias voltages an essential feature to obtain the desired super-linear behavior. The planar gate structure for that device is formed on the mesa surface. Electron transport occurs from the N + Source region and the inversion layer channel region through a transition region into the N-drift region. The constriction of current flow in the transition region adds to the on-resistance of the structure and limits the maximum drain current (i.e. the compression current).

In this chapter, a super-linear (SL) MOSFET structure is described which utilizes the charge-coupling concept exploited in the above device structure but relies up on a trench gate region formed within the mesa region [1]. The trench gate structure eliminates the transition region resulting in superior on-resistance and compression current. When compared with the trench gate GD-MOSFET structure described in Chapter 6, this structure is easier to fabricate because the gate is not formed within the same trench as the source connected deep trench electrode. The super-linear...

Products & Services
Trench Shoring Equipment
Trench shoring equipment includes trench shields and other shoring devices that are used to prevent a dug trench from caving-in on workers or equipment.
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.
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.
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).
Diodes are electronic components that conduct electric current in only one direction, functioning as a one-way valve. Diodes are manufactured using semiconductor materials such as silicon, germanium or selenium and are used as voltage regulators, signal rectifiers, oscillators and signal modulators / demodulators.

Topics of Interest

Overview The commercial introduction of the silicon RF power LD-MOSFETs in the 1990's was widely accepted by the cellular base station design community due to its superior linearity when compared...

Overview 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...

Overview The vertical double-diffused power MOSFET structure discussed in the previous chapter operates by blocking voltage across a P/N junction where the depletion occurs primarily on the lightly...

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...