Atomically controlled CVD processing of group IV semiconductors for ultra-large-scale integrations

Abstract

One of the main requirements for ultra-large-scale integrations (ULSIs) is atomic-order control of process technology. Our concept of atomically controlled processing is based on atomic-order surface reaction control by CVD. By ultraclean low-pressure CVD using SiH 4 and GeH 4 gases, high-quality low-temperature epitaxial growth of Si 1−x Ge x (100) (x=0–1) with atomically flat surfaces and interfaces on Si(100) is achieved. Self-limiting formation of 1–3 atomic layers of group IV or related atoms in the thermal adsorption and reaction of hydride gases on Si 1-x Ge x (100) are generalized based on the Langmuir-type model. By the Si epitaxial growth on top of the material already-formed on Si(100), N, B and C atoms are confined within about a 1 nm thick layer. In Si cap layer growth on the P atomic layer formed on Si 1−x Ge x (100), segregation of P atoms is suppressed by using Si 2 H 6 instead of SiH 4 at a low temperature of 450 °C. Heavy C atomic-layer doping suppresses strain relaxation as well as intermixing between Si and Ge at the Si 1−x Ge x /Si heterointerface. It is confirmed that higher carrier concentration and higher carrier mobility are achieved by atomic-layer doping. These results open the way to atomically controlled technology for ULSIs.

Novel Si–Ge–C superlattices and their applications

“…This capability has been demonstrated for group-IV materials utilizing semiconductor production equipment [25,26]. However, it is recognized that self-limiting growth may present a significant challenge regarding the deposition time for total thickness of a SL, compared to the deposition time for conventional SiGeC random alloys.…”

Atomic-order thermal nitridation of group IV semiconductors for ultra-large-scale integration

“…Atomically controlled processing has become indispensable for the fabrication of Si-and Ge-based ultra-small devices and heterodevices for ultra-large-scale integration because high performance devices require atomic order abrupt heterostructures and doping profiles as well as strain engineering due to introduction of Ge into Si. Our concept of atomically controlled processing is based on atomic-order surface reaction control in Si-based chemical vapor deposition (CVD) growth [1][2][3][4][5]. Introduction of N atomic layer at the interface between the high-k dielectric and the channel has been employed to suppress the interface trap formation [6].…”

“…Nevertheless, the goal is to create group IV semiconductors with high mobility as well as high carrier concentration by strain control for ULSIs using atomically controlled processing. Self-limiting formation of 1-3 atomic layers of group IV or related atoms in the thermal adsorption and reaction of hydride gases (SiH 4 , GeH 4 , NH 3 , PH 3 , B 2 H 6 CH 4 and SiH 3 CH 3 ) on Si(100), Si 0.5 Ge 0.5 (100) or Ge(100) at the temperature below around 500 °C were generalized based on the Langmuir-type model [1,3,5]. In many cases, hydride molecules are adsorbed and react simultaneously on the surface, as shown in figure 1 [3,5].…”

“…Self-limiting formation of 1-3 atomic layers of group IV or related atoms in the thermal adsorption and reaction of hydride gases (SiH 4 , GeH 4 , NH 3 , PH 3 , B 2 H 6 CH 4 and SiH 3 CH 3 ) on Si(100), Si 0.5 Ge 0.5 (100) or Ge(100) at the temperature below around 500 °C were generalized based on the Langmuir-type model [1,3,5]. In many cases, hydride molecules are adsorbed and react simultaneously on the surface, as shown in figure 1 [3,5]. Moreover, atomic-layer doping was performed by Si or Si 1−x Ge x epitaxial growth on N [3,7,8], P [3,5,9,10], B [11], C [5,12], Si [10] atomic layer already-formed on Si or Si 1−x Ge x surface.…”

“…In many cases, hydride molecules are adsorbed and react simultaneously on the surface, as shown in figure 1 [3,5]. Moreover, atomic-layer doping was performed by Si or Si 1−x Ge x epitaxial growth on N [3,7,8], P [3,5,9,10], B [11], C [5,12], Si [10] atomic layer already-formed on Si or Si 1−x Ge x surface. Especially, atomic layer doping of P and B in Ge epitaxial growth was performed at 300 °C.…”