Question

The integrated circuit is develop by various fabrication technique such as:
- Thermal oxidation
- Photomask and photolitography
- Plasma etching
- Diffusion of impurity atoms
Describe the basic steps in forming a PN junction by identifying the terms above. Draw
the suitable diagram.

Answer 1

PICTORIAL STEPS IN THE FABRICATION OF DIFFUSED P-N JUNCTION 1.Oxidize the Silicon wafer. 』』 2.Apply a layer of photoresist. Photoresist 3.Expose photoresist through mask A. UV Ray sesssssssss Mask 4. Remove unexposed photoresist. 5. Use HF etch to remove Sio, windows, Etched out Sio 6. Remove photoresist and diffuse Boron through windows in the SiO2 layer. Diffused Boron CSScanned with CamScanner

7.Evaporate Aluminum onto the surface. Aluminum 8.Using steps 2-4 each away Aluminum except in P - contact areas. C Scanned with CamScantrer

- + zone. The bout Thermal anilection: The cleaned pilian wafere placed in a quants belt between hoo wafer quarta silicon wafer is then bushed very gently into the zone of tre heated (ooooed nilagen ambert furnace Onidation broam in out by three step (1) middle Guidation Cat wet onidation and (3) Again day andations a It is a We used as a (3) Photmask and phoblithography & gt process by which we get the proper structure of the device on aufera negative fonoforesint , Diffusion area bright field mask Staho involved are ( waking of photoressat by spinning frowns Prebaking ov Enbone Dewelopment Photoresat o Portbacking % Hard (hefo resist gumoval Pluma ething type silicon jufer iso unpolished So bolishing is required and is done by of Noh solution at temb. asoc for 3 b5 minuter Offusion of impunity atom f 2012 Casca ned with CamScanner