(ZA9109399-A)      Method comprises applying to a portion of the surface of a semiconductor substrate an oxide forming mask layer which contains dopant. The semiconductor substrate with the mask layer is heated to a temp. sufficient for diffusion of part of the dopant from the mask layer to the semiconductor substrate. Undersirable auto-doping of the unprotected surfaces of the semiconductor substrate takes place during the doping process, for which reason the auto-doped areas of the semiconductor substrate are etched away by alkaline etching or plasma etching. The mask layer constitutes a protective barrier for the doped areas below the mask layer.    USE/ADVANTAGE -   In the prodn. of a solar cell with two doped areas of the P and N conductor types, respectively, the distance between the two doped areas may be used for adjusting the gradient of the dark current with a diode biassed in the blocking dire    (JP5508742-W)      Mfr. of doped areas on semiconductor components involves applying a source layer contg. a first type dopant to a portion of the substrate surface and heating it to a temp. sufficient to cause diffusion of part of the dopant from the source layer to the substrate.    Undesirable auto-doped areas on unprotected surfaces of the substrate, formed during the process, are etched away using the source layer as a protective mask for underlying doped areas. A second source layer with a second type dopant is then applied to another portion of the semiconductor surface and processed as before.    Substrate is crystalline Si. Source layers are selected from TiO, TiO2, Al2O3, SnO2 and Si3N4. Dopants are selected from P, B, As and Sb.    USE/ADVANTAGE -   Useful in the mfr. of a solar cell. The use of highly toxic HF acid for etching and photoresist masking is avoided. Also the number of high temp. process steps is significantly reduced compared with prior art.    (US5461002-A)      Doped areas are formed on semiconductor components by (a) applying one source layer contg. a 1st dopant to form protected surface portions, leaving unprotected portions not covered by the source layer, (b) heating to a temp. sufficient for diffusion of part of the dopant from the source layer into the protected surface portions to form protected doped areas in the substrate, autodoping of the unprotected surface portions also occurring, and (c) etching away enough of the unprotected surface portions to remove the unprotected doped areas. The source layer is thick enough such that while its thickness will be reduced during etching, it will not be completely removed, thus providing a protective barrier against any removal of the protected doped areas during etching. The source layer is pref. Si, and the dopant is TiO2, Al2O3, SnO2 or Si3N4, or P, B, As or Sb.    USE/ADVANTAGE -   For mfg. solar cells. Simple prodn. with reasonable efficiency.