代写VE320 Intro to Semiconductor Devices Summer 2024 — Problem Set 7代做回归

VE320 Intro to Semiconductor Devices

Summer 2024 — Problem Set 7

Due: 11:59 pm 28th July

1)    Several conceptual questions

a)   Explain the difference in the I-V relationship between the Schottky barrier diode and the Ohmic contact diode.

b)  Explain the difference in the I-V relationship between the metal-semiconductor and the two-terminal MOS structure.

c)   Explain the reason why there’s a maximum depletion layer width.

2)    Energy band diagrams

a)   Draw the equilibrium energy band diagram of a Schottky barrier diode and an Ohmic contact diode (both with ann-type semiconductor).

b)  Draw the equilibrium energy band diagram of the two-terminal MOS structure if the work function of the metal is bigger than that of the semiconductor.

3)    A Schottky diode at T =300K is formed with Pt on n-type silicon with a doping

concentration of Nd  = 5 × 1015 cm −3 . The barrier height is found to be  φBn   =   0.89v. The effective Richardson constant is  A∗ = 120A/k2 -cm2 . Determine (a) φn, (b)  vbi, (c)  JST, and (d)  va    such that Jn   = 5A/cm2 .

4） A Schottky diode with n-type GaAs at T = 300K yields the plot shown in the

Figure below, where the unit of C ′ is  fF/cm2. Determine (a)  vbi, (b)  Nd, (c)  φn , and (d)  φB0. You can approximately read the graph below.

5)    The high-frequency C–V characteristic curve of a MOS capacitor is shown in the figure below. The area of the device is  2 × 10 −3cm2 . The metal-semiconductor work function difference is  φmS   = −0.50v, the oxide is SiO2, the semiconductor is silicon, and the semiconductor doping concentration is  2 × 1016 cm −3 . (a) Is the semiconductor n or p-type? (b) What is the oxide thickness? (c) What is the equivalent trapped oxide charge density?

6)    The high-frequency C–V characteristic curve of a MOS capacitor is shown in the figure below. The oxide is SiO2 and the semiconductor is silicon. The area of the MOS capacitor is  3 × 10 −3cm2 . (a) Is the semiconductor component of the MOS capacitor doped n-type or p-type? (b) Draw the MOS capacitor energy band diagram corresponding to point (2) on the C – V characteristic. (c) Draw the block charge diagram corresponding to point (1) on the C – V characteristic. (d) What is the oxide thickness? (e) Determine  xdT and the associated semiconductor doping concentration for the given MOS capacitor.

7)    Consider ann-channel depletion mode MOSFET with ann polysilicon gate. The n-channel doping is  Nd   =  1015 cm −3   and the oxide thickness is 500 Å . The equivalent fixed oxide charge is  Qs(′)s   = 1010 cm −2 . The metal-semiconductor work function difference is  φms   = −0.272v. Then-channel thickness is equal to the maximum induced space charge width. (Disregard the space charge region at then-channel–p-substrate junction.) (a) Determine the channel thickness and (b) calculate the threshold voltage.