A. For impurity diffusion in semiconductor, concentration gradient is the only essential requirement. B. Annealing is a mandatory step after ion-implantation. C. Wet etching is normally anisotropic D. High temperature is required for the growth of $SiO_2$ because oxidation reaction takes place at high temperature E. Bird's beak formation is a characteristic of LOCOS isolation Choose the correct answer from the options given below:
Semiconductor Fabrication Concepts Analysis
Evaluating each statement regarding semiconductor processing:
- Statement A: Impurity diffusion relies on a concentration gradient, but other factors like temperature are also essential. Thus, A is incorrect.
- Statement B: Annealing post-ion implantation is mandatory to repair lattice damage and activate dopants. Thus, B is correct.
- Statement C: Wet etching is generally isotropic, unlike anisotropic dry etching. Thus, C is incorrect.
- Statement D: High temperatures are necessary for $SiO_2$ growth kinetics. The statement's explanation is circular. Thus, D is incorrect.
- Statement E: Bird's beak formation is characteristic of the LOCOS isolation process. Thus, E is correct.
Final Answer Selection
Statements B and E are correct. This corresponds to Option 3.
Important Questions from Semiconductor Process Flow
Which one of the following processes is preferred to form the gate dielectric (SiO2) of MOSFETs?
Arrange the following in the correct sequence of steps for MOS fabrication
A. Wafer formation
B. Photolithography
C. Oxidation
D. Gate and source/drain formation
E. Metallization
Choose the correct answer from the options given below:Which of the following statements are true for optical photoresists
A. Solubility of a photo-resist changes on exposure to light in developer solution.
B. Solubility of a photo-resist does not change on exposure to light in developer solution.
C. A negative photo-resist on exposure to light becomes less soluble in developer solution.
D. A positive photo-resist on exposure to light becomes more soluble in developer solution.
Choose the correct answer from the options given below:- In particle beam lithography, the resolution depends upon :
Arrange the given process steps in sequence for self-aligned gate formation.
A. Thermal oxidation to grow gate oxide.
B. Polysilicon deposition
C. Photolithography using gate mask
D. Etching of polysilicon and oxide
E. Source/drain diffusion
Choose the correct answer from the options given below:
