Taking into account reactant depletion, gas diffusion, surface processes, a i d a fourth basic step that is connected with the influence of surface equilibria, the compensation of depletion is treated for both host niaterial deposition and in-situ doping. So, some aspects can be given for the realization of layer honiogeneity in epitaxy, as well as in LPCVL). I n conclusion, the terniinology of border cases in CVD is discussed.Unter Berucksichtigung tier Reaktantenverarmung, der Gasdiffusion, der Oberfliichenprozesse und eiiies vierten, Init den1 EinfluB der Oberfliichengleichgewichte verbundenen Grondschrittes wird die Verariiiungskompensation fur Ablagerung des Wirtsrnaterials und in-situ-Uotierung genieinsam behandelt. Uarnit koniien einige Gesichtspurikte fur die Eealisierung der Schichthornogenitiit sowohl hei der Epitxie als auch bei Unterdruck-Ablagerungsprozessen angegeben werden. AbschlieBend wird die Terrninologie von Grenzfiillen bei CVD-l'rozessen diskutierb.
Four basic steps in CVDFor chemical vapour deposition, the partial pressure drop of the starting reactant r from its input value P,, i to zero can be divided into four basic steps, as is shown by Figure 1. Here, the global circuit representation that has been given by the foregoing paper (Part I, Fig. 1 a) is specified by subdividing the resistance R according toThe corresponding stationary "equations of motion" for the atomic incorporation current density are (1) p r , i -P r , m Pr,m -P r , s -P r , s -P r , e P r , e
RIVA s in Part I, the occurrence of intermediate products is not considered explicitly. Only the main features will be given, which are indispensable for the following discussions. The four resistances are:1.) The reactant depletion resistance RI, which has turned out in Part I (in the case of negletable downstreani diffusion) to increase linearly in the downstreani direction z , and to be independent on species r , if depletion is compensated. If not, RI changes nonlinearly with z , and it beconies dependent on the three resistances that follow.
11.) The gas diffusion resistance RII, which is connected with the drop from the yaveraged partial pressure PI,,,, to P,, the actual surface value of P, (both at distance z from the input). Without thermodiffusion, it is 89'
