Epitaxial Growth and Properties of Silicon on Alumina-Rich Single-Crystal Spinel

Abstract

Mobilities similar in magnitude to bulk silicon mobilities may be realized in 1.4 to 1.6µ thick films on flame fusion magnesium aluminate spinel, for carrier concentrations greater than ≈2×1016 cm−3 (p‐type). The electrical properties of these films are not significantly altered by thermal oxidation at 1200° C for 1 hr. In this carrier concentration range the electrical characteristics are not highly dependent on the deposition rate within the limits investigated. For carrier concentrations between 5×1015 and 2×1016 cm−3 (p‐type) the “as deposited” film mobilities are near bulk values, but the mobilities are degraded by the thermal oxidation. In this doping range the electrical properties of the oxidized films are critically dependent on the deposition rate. The films deposited at the higher rates are altered less on oxidation than films deposited at the lower rates. Using a growth rate of 2 µ/min, a mobility of 300 cm2/V‐sec (≈80% of bulk) at Nnormala=4×1015 cm−3 may be realized in a film oxidized 1 hr at 1100°C. Below this carrier concentration the mobility of the oxidized films decreases sharply with decreasing carrier concentrations. Minority carrier lifetimes as high as 40 nsec have been realized in 4µ thick films of silicon on spinel. The carrier concentration as a function of temperature and mobility as a function of thickness of silicon on spinel have been measured.

A Comparison of the Semiconducting Properties of Thin Films of Silicon on Sapphire and Spinel

“…It has been demonstrated that, particularly when spinel is used as the substrate material, the semiconducting properties of the low carrier concentration films are considerably more dependent on the deposition conditions than are the properties of the high carrier concentration films (10).…”

“…Excellent progress has been made, and semiconducting properties useful for application in commercial devices have been realized (4)(5)(6). Spinel has been considered as a possible alternate substrate because of the relatively good crystallographic match to, and relatively low chemical reactivity with, silicon (7)(8)(9)(10). Higher mobilities have been achieved for some, but not all carrier types, orientations, and thicknesses of silicon on spinel (11,12).…”

A Comparison of the Hole Mobility and Early Growth of Epitaxial Silicon on Flame Fusion, Flux, and Czochralski Spinel

“…Single crystal low angle electron diffraction patterns are obtained on hydrogen etched flame fusion spinel surfaces. In this carrier concentration range the hole mobilities are degraded by less than 5%, and the magnitude of the degradation is relatively insensitive to the growth rate (9). The after-oxidation hole mobility of 320 cm2/V-sec (n~ ----1.1 x 10 TM cm -3) is ~92% of the bulk reference value.…”

“…Higher hole mobilities have been observed in (111) silicon on (111) spinel than in (100) silicon on (100) spinel (9). But the mohilities of thin (100) silicon on the (1~02) sapphire have been higher than in (111) silicon on (0001) sapphire (23).…”

Crystallization—Part I - Transport Phenomena of Nucleation and Crystal Growth

“…In (20Ga. 122Ga) (Zn,Cd)S InAs (88 Ga) ZnSe InSb (35Ga,41 39Ga,50Ga,56Ga,65Ga,90Ga,91 Ga. 95Ga, 106Ga, 137Ga, 140Ga, 176Ga) (181Ga) (12Ga,13Ga. 24Ga,66Ga,81 Ga, 135 Ga, 178Ga) (31 Ga) ' (2Ga,30Ga,31 Ga from dilute (10~6-10~3 M) ionic solutions.…”