In/Sb is integrated with Si by a process of high energy heavy ion beam mixing. The samples of In/Sb deposited on the Si substrate were irradiated using 100 MeV Au ions having fluences from 1 × 1012 to 6 × 1013 ions cm−2. Phase formation due to ion beam mixing was detected using high-resolution x-ray diffraction measurements. X-ray photoelectron spectroscopy measurements indicated that both In and Sb were embedded in the Si substrate with an irradiation dose of 3 × 1013 ions cm−2. Formation of InSb phase was observed in the irradiated sample, at a fluence of 1 × 1013 ions cm−2and higher, without any post-irradiation annealing.
A small Fresnel lens array was diamond turned in a single crystal (0 0 1) InSb wafer using a half-radius negative rake angle (−25°) single-point diamond tool. The machined array consisted of three concave Fresnel lenses cut under different machining sequences. The Fresnel lens profiles were designed to operate in the paraxial domain having a quadratic phase distribution. The sample was examined by scanning electron microscopy and an optical profilometer. Optical profilometry was also used to measure the surface roughness of the machined surface. Ductile ribbon-like chips were observed on the cutting tool rake face. No signs of cutting edge wear was observed on the diamond tool. The machined surface presented an amorphous phase probed by micro Raman spectroscopy. A successful heat treatment of annealing was carried out to recover the crystalline phase on the machined surface. The results indicated that it is possible to perform a 'mechanical lithography' process in single crystal semiconductors.
Since the high thermal resistance of InGaAs metamorphic high electron mobility transistors (MHEMTs) limits their applicability, thermal management should be taken into account when designing the device structure. In this study, structural effects on heat dissipation in InGaAs MHEMTs were carefully investigated and experimentally validated. With an air bridge thickness of 10 µm and a gate pitch distance of 24 µm, the maximum channel temperature in a flip-chip bonded device was noticeably reduced from 132 to 106 °C (i.e. corresponding thermal resistance from 252.17 to 178.14 K W−1). Improved heat dissipation with the proposed structure was experimentally validated using backside-mounted devices by an infrared temperature measurement method. Source:IOPscience