The proposed work will focus on synthesis and advanced characterization studies of the next generation of intrinsic and doped Ge1-ySny and Ge1-x-ySixSny alloy systems at technologically relevant concentrations of up to 10 % Sn (y = 0.10). These include thick Ge1-ySny layers grown directly on Si substrates and ternary Ge1-x-ySixSny grown directly on Si, GaAs or Ge substrates depending on the specific application. To produce the targeted materials at the desired concentrations with device-quality crystal properties, specifically designed growth protocols and newly discovered deposition chemistries will be employed. The latter involve new molecular CVD precursors, such as Ge3H8, Ge4H10, and Si4H10, which are expected to provide an unprecedented level of control over the substitutional incorporation of Sn and the formation of bulk-like films directly on Si and Ge platforms under CMOS-compatible conditions. A desired outcome is to achieve layer formats exceeding 1 m, with the goal of clearly separating the Si/alloy interface from the active device components. The work will also include an initial kinetic study of the growth behavior that may allow a rational exploration of the deposition parameter space and provide the means for systematic refinement of process conditions. To enable the development of the proposed materials from a device application perspective, the key structural, optical and electrical properties of the fabricated Ge1-ySny and Ge1-x-ySixSny alloys will be investigated as functions of Sn and/or Si alloy composition and post-growth processing conditions. These studies will focus specifically on evaluating direct and indirect gap emission (PL), impurity and defect levels, mobilities, conductivity, carrier concentrations, and optical absorption. Samples will be delivered to researchers at AFRL, Wright Paterson Air Force Base, to perform standard characterizations and 4 evaluations of the materials with emphasis on areas complementary to the techniques available at ASU. If successful, the program will deliver a broad range of new alloys that extend the properties of conventional Ge-on-Si technologies beyond 1.55 m and propel the rapid development of a range of novel optical devices on Si beyond the capabilities of current technologies.
|Effective start/end date||12/21/12 → 3/11/14|
- DOD-USAF: Air Force Research Labs (AFRL): $148,383.00