Samuel Emil Blum

Laser enhanced electroplating and maskless pattern generation

Maskless plating has been achieved through a new technique that utilizes a cw or pulsed laser, focused onto an electrode in an electroplating bath. In the region of optical absorption on the cathode, plating enhancement rates on the order of 103 occur for optical power densities on the order of 104 W/cm2. Laser scanning produces a plating pattern along the scanning path. A qualitative theory based on convective mass transport is used to explain the results.

Photo‐oxidation of silicon monoxide to silicon dioxide with pulsed far‐ultraviolet (193 nm) laser radiation

Silicon monoxide films (1000–5000 A thick) are converted to silicon dioxide when irradiated in air with pulses (∼15 n half‐width) of 193‐nm radiation (40–110 mJ/cm2) from an excimer laser. The quantum efficiency of the process has a minimum value of 0.014.

Giant microwave losses in a YBaCuO bicrystal

We have observed a large peak in microwave losses, as a function of temperature, in a superconducting Y1Ba2Cu3O7 bicrystal containing a large‐area, low‐angle grain boundary. The maximum observed loss was approximately twice the normal state loss. We attribute the peak to enhanced losses occurring within the grain boundary due to the concentration of microwave field lines in the boundary as they are expelled from the superconducting regions. At high microwave powers, bistability in the absorption was observed, resulting in hysteretic absorption curves as a function of both T and magnetic field H.

Shallow zinc diffusion in liquid phase epitaxial GaAs and (GaAl)As at 600 °C

The diffusion of zinc into GaAs and (GaAl)As was studied using a high resolution microsectioning technique. Diffusions were performed into epitaxially grown thin layers comparable to those used in injection laser structures; several boat grown GaAs were also studied. The diffusions were done at a temperature commonly used in device processing; a three‐phase diffusant was used to preclude sample dissociation and damage. A diffusion coefficient of Zn in GaAs of 1.4×10−11 cm2 s−1 was obtained, and this is in good agreement with the extrapolation of the values obtained at higher temperatures. A marked difference in the diffusion profiles of GaAs and (GaAl)As was observed.