Contacts to Semiconductors - Fundamentals and Technology
If the voltage difference between the source and drain is high enough, the inversion layer will pinch off before the drain, even in the presence of a greater-than-threshold gate voltage. This creates heavily doped p channel stop which prevent conduction between devices. Next, the SiO2 is etched away and a layer of field oxide is deposited, and more boron is doped in. This is to modify the doping concentration in the channel.
Contacts to semiconductors : fundamentals and technology
Next, the field oxide is removed over the active device area and the gate oxide is grown in the center. A poly silicon layer is deposited on top of the gate and heavily doped to be conductive. The gate itself shields the doping so that the regions are defined by the gate. Figure 2: Inversion layer in a conducting MOSFET The slanted shape of the inversion layer is due to the fact that charge carriers along the channel experience a combination of voltage potentials from the gate, source, and drain.
Questions Q1: Why is the insulator present? What would happen to the device if it were absent?
Q2: If the gate voltage is nonzero but below the threshold voltage, and the source to drain voltage is zero, what does the inversion layer look like? Q3: How does the device fail if it gets too hot? When you buy through links on our site, we may earn an affiliate commission. Taken this course? Share your experience with other students.
Semiconductor p-n Junction and Contacts | Micro-Learning Courses | Temasek Polytechnic
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