Characterization of Shallow, Undoped Ge/SiGe Quantum Wells Commercially Grown on 8-in. (100) Si Wafers

Abstract

Hole spins in Ge quantum wells have shown success in both spintronic and quantum applications, thereby increasing the demand for high-quality material. We performed material analysis and device characterization of commercially grown shallow and undoped Ge/SiGe quantum well heterostructures on 8-in. (100) Si wafers. Material analysis reveals the high crystalline quality, sharp interfaces, and uniformity of the material. We demonstrate a high mobility (1.7 × 105 cm2 V–1 s–1) 2D hole gas in a device with a conduction threshold density of 9.2 × 1010 cm–2. We study the use of surface preparation as a tool to control barrier thickness, density, mobility, and interface trap density. We report interface trap densities of 6 × 1012 eV–1. Our results validate the material’s high quality and show that further investigation into improving device performance is needed. We conclude that surface preparations which include weak Ge etchants, such as dilute H2O2, can be used for postgrowth control of quantum well depth in Ge-rich SiGe while still providing a relatively smooth oxide–semiconductor interface. Our results show that interface state density is mostly independent of our surface preparations, thereby implying that a Si cap layer is not necessary for device performance. Transport in our devices is instead limited by the quantum well depth. Commercially sourced Ge/SiGe, such as studied here, will provide accessibility for future investigations.

Characterization of Mn5Ge3 Contacts on a Shallow Ge/SiGe Heterostructure

“…The Ge/SiGe heterostructures used consist of a 15 nm Ge quantum well at a depth of 30 nm with barriers and a Si capping layer with an approximate thickness of 1 . Details about the growth and transport properties of the Ge/SiGe heterostructure have been previously reported [ 13 ]. The deposition of approximately 100 of Mn occurred at a pressure of and a rate of Å/ .…”

“…Recently, there have been demonstrations of Ge/SiGe quantum wells with mobilities in the / / range [ 11 , 12 ]. Large-scale wafer growth of high-quality Ge/SiGe quantum materials has now opened access for further research [ 12 , 13 ].…”

Growth and Characterization of SiGe/SiO2 Core/Shell Nanocrystals on Insulators

“…Silicon–germanium alloy (Si 1– x Ge x ) is emerging as a crucial material for future advances in silicon-based devices. This composite presents a preparation technique that is fully compatible with existing silicon technology, paving the way to various applications. − Notably, it is recommended as a substitute for silicon in several applications in nanoelectronics and photonics due to several properties, such as the low melting temperature of germanium compared to silicon, as well as favorable physical properties at lower temperatures than those required for silicon. − The ability to process the Si 1– x Ge x alloy at lower temperatures is of particular importance, aligning with the current trend in submicrometer integrated circuit device fabrication, where high temperatures are increasingly less compatible. In addition, Si 1– x Ge x alloy crystals offer a new degree of freedom to optimize their optoelectronic properties by modifying the relative proportions of silicon and germanium. − Si 1– x Ge x alloy nanocrystals present a unique opportunity to control the band gap energy by tuning the germanium content .…”

High-Performance Ge PIN Photodiodes on a 200 mm Insulator with a Resonant Cavity Structure and Monolayer Graphene Absorber for SWIR Detection

“…Commonly used SWIR optoelectronic materials including InGaAs, − HgCdTe, − PbS, − and mainstream InGaAs SWIR imaging chips have been commercially available for a long time. − However, there are some technical difficulties, such as small substrate diameter, high wafer cost, expensive chip manufacturing cost, low yield rate, and toxicity. , In addition, these SWIR chips are not compatible with the CMOS process production lines, which require a separate production line to avoid inevitable contamination. Group IV Ge (Sn) semiconductor material was regarded as one of the most promising candidates to overturn the current SWIR imaging technology due to their excellent photoelectric response in the SWIR band and compatibility with the standard CMOS process, thereby making Ge an ideal absorption layer for the high-performance SWIR photodetectors. − …”