【正文】 2023w 1 業(yè) 余生活要有意 義 ，不要越 軌 。 04:48:2604:48:2604:48Monday,2023w 1少年十五二十 時(shí) ，步行 奪 得胡 馬騎 。 04:48:2604:48:2604:48Monday,2023w 1行 動(dòng) 出成果，工作出 財(cái) 富。 04:48:2504:48:2504:48Monday,grown junctions in the ingot.n Repeated counterdopings can produce multiple junctions within the crystal.w Disadvantages n Inability to produce differently doped areas in different parts of the wafer.n The thickness and planarity of grown junctions are difficult to control.n Repeated counterdopings degrade the electrical properties of the silicon.The Planar Processw Advantages:? The planar process does not require multiple counterdopings of the silicon ingot.? This process allows more precise control of junction depths and dopant distributions.Methods of planar processw Diffusionn A uniformly doped ingot is sliced into wafers. n An oxide film is then grown on the wafers.n The film is patterned and etched using photolithography exposing specific sections of the silicon.n The wafers are then spun with an opposite polarity doping source adhering only to the exposed areas. n The wafers are then heated in a furnace (800173。setsto capable of high throughputs 173。environmentSiO2areasbyareasprotectiveMOSdensitiesvariousformisaschargesinterferelayersan) control MOS devices 173。cycleafterato.thecalledtimethetoonthethat4345isfirstawhichtheistheThisofwithprocesscontaminantsashm) oxides are used for field oxides (isolate devices from one another )173。siliconslowly.interfacelowtheofoxidefieldsuchbetogatelayers,processsolutionpatternedor are in general isotropic (not used to etch features less than ≈ 3 181。 CH3COOH+HNO3+H3PO4 What is a plasma (glow discharge)?w A plasma is a partially ionized gas made up of equal parts positively and negatively charged particles. w Plasmas are generated by flowing gases through an electric or magic field. w These fields remove electrons from some of the gas molecules. The liberated electrons are accelerated, or energized, by the fields. w The energetic electrons slam into other gas molecules, liberating more electrons, which are accelerated and liberate more electrons from gas molecules, thus sustaining the plasma.Dry or Plasma EtchingDry or Plasma EtchingDry or Plasma EtchingCombination of chemical and physical etching – Reactive Ion Etching (RIE) DirectionaltowardFabrication4:48:25214:484:48:25214:484:48:26214:48February2023w 1知人者智，自知者明。February2023w 1不知香 積 寺，數(shù)里入云峰。February2023w 1乍 見(jiàn) 翻疑夢(mèng)，相悲各 問(wèn) 年。Ion ImplantationComparison of Diffusion and Ion Implantationw Diffusion is a cheaper and more simplistic method, but can only be performed from the surface of the wafers. Dopants also diffuse unevenly, and interact with each other altering the diffusion rate.w Ion implantation is more expensive and plex. It does not require high temperatures and also allows for greater control of dopant concentration and profile. It is an anisotropic process and therefore does not spread the dopant implant as much as diffusion. This aids in the manufacture of self173。enhancenegativeIn can etch j