Sputtered amorphous silicon, hydrogen

As a second example of the application of ion-beam analysis techniques to semiconductors, we take the calibration of IR absorption measurements of the hydrogen content of sputtered amorphous silicon and silicon nitride. In early measurements, the hydrogen content of glow-discharge a-Si H deduced from IR absorption measurements, using ablsinitio calculations of the absorption cross section of the Si—H IR absorption bands, was com-... 

That hydrogen is responsible for the large reduction of the dangling bond density in amorphous silicon is demonstrated by studies of films grown by sputtering of silicon with an inert gas (Paul et al., 1976). When hydrogen is added to the argon carrier gas, the spin density is reduced to 1016/cm3, and the films can be doped. In contrast, sputtered amorphous... 

Figure 16 (Street et al., 1986) shows the typical sample structure, consisting of three layers of a-Si H. Results using this technique have been reported for samples grown by the rf glow discharge of silane and by rf sputtering (Shinar et al., 1989). The first layer is hydrogenated amorphous silicon, deposited under conditions that yield high quality films (i.e., deposition temperature of 230°C, low growth rate) and is typically two microns thick. Next a layer of approximately 1000 A is deposited, whereby...

IR and Raman spectroscopy were used to characterise hydrogenated silicon thin films formed by magnetron r.f. sputtering, or by hot-wire CVD. An IR study (vSiH) has been made of the photoinduced changes in the structure of undoped hydrogenated amorphous silicon, a-Si H.379 IR bands due to Si-H-Si units were reported for silicon-isotopically enriched silicon crystals.380... 

Plasmas are also used for the low temperature deposition of thin solid films, for example amorphous hydrogenated silicon, diamond, and a host of other materials. Since the fundamentals of plasma physics and chemistry are the same for both plasma etching and plasma assisted chemical vapor deposition (PECVD), the latter will only be discussed briefly in Section 6.6. A review of PECVD can be foxmd in [14]. Sputtering is discussed by Chapman [15], and plasma polymerization is covered by Yasuda [16]. 

The deposition of amorphous hydrogenated silicon (a-Si H) from a silane plasma doped with diborane (B2 Hg) or phosphine (PH ) to produce p-type or n-type silicon is important in the semiconductor indusby. The plasma process produces films with a much lower defect density in comparison with deposition by sputtering or evaporation. 

---