Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 47: Transport in high magnetic field/quantum-Hall-effect

HL 47.8: Talk

Thursday, March 29, 2007, 17:30–17:45, H14

Shadow epitaxy technique for fabricating complex coplanar 2D structures — •N. Isik, S. F. Roth, M. Bichler, A. Fontcuberta i Morral, and M. Grayson — Walter Schottky Institute ,Technische Universität München, Am Coulombwall 3, 85748 Garching , Germany

Advanced growth techniques are required to fabricate complex 2D heterostructures, however such approaches often need special postgrowth processes, i.e. regrowth over a patterned back gate, selective ion implantation, cleaved-edge overgrowth, flip-chip bonding, V-groove regrowth. We introduce here a new shadow epitaxy technique whose most important advantage is the ability to grow complex devices with a single growth process, requiring only standard photolithography to achieve a final device. Our technique requires only tall rectangular pieces of GaAs wafer mounted perpendicular to the substrate for creating shadows. During the growth, the substrate is arranged at specific angles relative to the cell positions in the MBE chamber causing specific layers of the heterostructure to be absent in the shadow region. By using this shadow epitaxy technique, two type of structures will be demonstrated. First, localized superlattice shadow structures are analyzed by using scanning electron microscopy (SEM). Second, the transport properties of modulation doped high mobility n− and p− type coplanar 2D shadows will be characterized.