Identify the MOSFET type: If the drain, source, and channel regions are p-type material and the device can operate in depletion as well as enhancement (depending on gate bias), which MOSFET is described?

Introduction / Context:
Understanding MOSFET channel type (n or p) and mode (depletion or enhancement) is crucial for selecting parts and predicting bias behavior. The description mentions p-type channel material and the ability to conduct at zero gate bias (depletion capability), which points to one specific device family.

Given Data / Assumptions:

• Drain, source, and channel are p-type regions.
• Device can operate in depletion (channel present at VGS = 0) and also respond to gate bias with either reduction or enhancement of channel carriers.
• Standard MOS structure with insulated gate.

Concept / Approach:
Depletion-mode MOSFETs have a physical channel at zero gate bias. If that channel is p-type, it is a p-channel D-MOSFET. Applying a more negative gate relative to source depletes the channel (reducing current), while applying a more positive gate can enhance conduction. In contrast, n-channel devices have n-type channels; describing all three regions as p-type contradicts an n-channel designation.

Step-by-Step Solution:

Verification / Alternative check:
Device symbols for depletion MOSFETs show a solid channel line; p-channel symbols use arrow and polarity conventions indicating hole conduction. Datasheets describe ID at VGS = 0 for depletion devices, confirming conduction without gate bias.

Why Other Options Are Wrong:

• n-channel D-MOSFET (option a) requires an n-type channel, not p-type.
• n-channel E-MOSFET (option c) lacks a channel at VGS = 0 and is the wrong polarity.
• p-channel E-MOSFET only (option d) is enhancement-only; the stem explicitly includes depletion capability.

Common Pitfalls:
Confusing depletion/enhancement modes with channel polarity or assuming enhancement-only behavior applies to all MOSFETs.

Final Answer:
Correct — p-channel D-MOSFET.