1. A method of fabricating a microlens, comprising:
forming a compound semiconductor layer having a reactive metal on a substrate;
etching the compound semiconductor layer, and forming a compound semiconductor layer pattern; and
partially removing a lateral surface of the compound semiconductor layer pattern, and forming a lens layer,
wherein the compound semiconductor layer is formed by a digital alloy method, the compound semiconductor layer includes a reactive layer containing the reactive metal and a semiconductor layer composed of a compound semiconductor containing no reactive metal, and the concentration of the reactive metal is higher in an upper position of the compound semiconductor layer.
2. The method according to claim 1, wherein the compound semiconductor layer is formed by repeatedly stacking the reactive layer and the semiconductor layer, and the reactive layer becomes thicker in an upper position of the compound semiconductor layer.
3. The method according to claim 1, wherein the compound semiconductor layer is formed by an epitaxial growth process.
4. The method according to claim 1, after forming the compound semiconductor layer, further comprising forming a screen layer on the compound semiconductor layer, the screen layer being formed of a material having an etch selectivity with respect to the compound semiconductor layer.
5. The method according to claim 4, wherein the screen layer is formed by an epitaxial growth process.
6. The method according to claim 5, further comprising removing the screen layer remaining on the lens layer after forming the lens layer.
7. The method according to claim 1, wherein partially removing the compound semiconductor layer pattern is performed by a wet etching process.
8. The method according to claim 7, wherein the reactive metal is aluminum (Al).
9. The method according to claim 8, wherein the reactive layer is formed of one selected from the group consisting of AlGaAs, InGaAlAs, and InGaAlN, and the semiconductor layer is formed of one selected from the group consisting of GaAs, InGaAs, and InGaN.
10. The method according to claim 9, wherein the wet etching process is performed using a BOE (buffered oxide etchant) as an etchant
11. A method of fabricating a microlens, comprising:
forming a compound semiconductor layer on a substrate by repeatedly stacking a reactive layer containing a reactive metal and a semiconductor layer containing no reactive metal using an epitaxial growth process, the reactive layer being thicker in an upper position of the compound semiconductor layer;
forming a screen layer on the compound semiconductor layer to protect a top surface of the compound semiconductor layer;
selectively etching the compound semiconductor layer and the screen layer, and forming a compound semiconductor layer pattern and a screen layer pattern;
forming a lens layer by etching a lateral surface of the compound semiconductor layer pattern, wherein an upper portion of the compound semiconductor layer pattern, in which the content of the reactive metal is high, is etched at a high etch rate, and a lower portion of the compound semiconductor layer pattern, in which the content of the reactive metal is low, is etched at a low etch rate; and
removing the screen layer pattern remaining on the lens layer, and exposing the lens layer.
12. The method according to claim 11, wherein the reactive metal is aluminum (Al).
13. The method according to claim 12, wherein etching the lateral surface of the compound semiconductor layer pattern is performed by a wet etching process using a BOE as an etchant.
14. The method according to claim 12, wherein the reactive layer is formed of one selected from the group consisting of AlGaAs, InGaAlAs, and InGaAlN.
15. The method according to claim 11, wherein the screen layer is formed by an epitaxial growth process performed in-situ during the formation of the compound semiconductor layer.
16. A microlens fabricated by a method comprising:
forming a compound semiconductor layer having a reactive metal on a substrate;
etching the compound semiconductor layer, and forming a compound semiconductor layer pattern; and
partially etching a lateral surface of the compound semiconductor layer pattern, and forming a lens layer,
wherein the compound semiconductor layer is formed by a digital alloy method and includes a reactive layer containing the reactive metal and a semiconductor layer composed of a compound semiconductor containing no the reactive metal, and the concentration of the reactive metal is higher in an upper position of the compound semiconductor layer.
17. The microlens according to claim 16, wherein the reactive metal is aluminum (Al), and the reactive layer is formed of one selected from the group consisting of AlGaAs, InGaAlAs, and InGaAlN.
18. The microlens according to claim 17, wherein the lens layer is formed by a wet etching process using a BOE as an etchant.
19. The microlens according to claim 16, wherein the compound semiconductor layer is formed by an epitaxial growth process.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
I claim:
1. A configuration for minimizing a Nel interaction, comprising:
a first asymmetrical artificial anti-ferromagnetic layer system having a first ferromagnetic sublayer, a second ferromagnetic sublayer, and a first spacer layer disposed between said first and second ferromagnetic sublayers;
a separating layer, said first ferromagnetic sublayer being oriented toward said separating layer and having a smaller layer thickness than said second ferromagnetic sublayer of said first asymmetrical artificial anti-ferromagnetic layer system; and
a second asymmetrical artificial anti-ferromagnetic layer system having a first ferromagnetic sublayer oriented toward said separating layer, a second ferromagnetic sublayer, and a second spacer layer disposed between said first and second ferromagnetic sublayers of said second asymmetrical artificial anti-ferrromagnetic layer system, said first ferromagnetic sublayer of said second asymmetrical artificial anti-ferromagnetic layer system having a smaller layer thickness than said second ferromagnetic sublayer of said second asymmetrical artificial anti-ferromagnetic layer system, and resulting total magnetizations of said first and second asymmetrical artificial anti-ferromagnetic layer systems being accumulated vectorially in a manner that compensates for the Nel interaction between said first ferromagnetic sublayer of said first asymmetrical artificial anti-ferromagnetic layer system and said first ferromagnetic sublayer of said second asymmetrical artificial anti-ferromagnetic layer system each being oriented toward said separating layer.
2. The configuration according to claim 1, wherein said first symmetrical artificial anti-ferromagnetic layer system is a reference layer system and said second asymmetrical artificial anti-ferromagnetic layer system is a memory layer system of a magneto-resistive memory cell.
3. The configuration according to claim 2, wherein said magneto-resistive memory cell is based on a tunnel effect and said separating layer is composed of a dielectric material and functioning as a tunnel barrier.
4. The configuration according to claim 3, further comprising at least one exchange bias layer disposed at a surface of said reference layer system lying remote from said tunnel barrier and a magnetization of said exchange bias layer is fixedly coupled to a magnetization of said reference layer system.
5. The configuration according to claim 4, wherein said exchange bias layer extends beyond dimensions of said reference layer system in a plane parallel to said tunnel barrier.